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guyslp

'89 de Ville - Heater Problems

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My car has decided to become utterly anemic as far as cabin heating. Today the outside temperature was 28 degrees F and I had the system set to 72 degrees F. I tried Econ, Auto, and Defrost modes and the result was the same: very, very cool "heat."

I can't decide whether the temperature of the air coming out of the foot vents or the defrost vents was warmer than ambient outdoor temperature because it was a mix of the existing cabin air (which the sun helped to warm up with the windows closed) with outdoor air or because there was a minimal amount of heat being generated by the heater core.

I bought the car last winter so I would have to have noticed this last year had it been present then.

I've been through this sort of thing before with other cars. I've checked the coolant level in the radiator and overflow tank and they're fine. I've seen this before for any one of several "usual reasons:"

  1. Blocked or partially blocked heater core (unlikely, I think)
  2. Malfunctioning heater water valve or actuator for same
  3. Thermostat stuck open which makes the engine take *forever* to reach operating (and heating) temperature.

I'm wondering if anyone has an opinion as to which is most likely/what I should be checking first.

Brian, who expected "inferno like" heat at the early stages of heating today, and didn't get that


Brian

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Bri the Tech Guy   http://britechguy.com
britechguy@gmail.com   (540) 324-5032
"If it's got you screaming, I'll help you stop!!"

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There is a way to display the engine coolant temperature on the climate control panel or fuel data panel - You could enter the onboard diagnostics and display the engine coolant temperature and monitor how long it takes for the engine coolant temperature to reach 192-195°. The display may read in celsius - if that is the case, you'd be looking for 89-91°. Someone who has a shop manual for this vintage of car should be able to post the information.

A plugged heater core is a possibility. Are both heater hoses hot to the touch after the car has been driven? If the outlet hose temperature is cooler than the inlet hose temperature, the heater core is restricted. The other possibility is the plastic "tee" that ties in the heater core inlet hose to the cooling system may have lost the orifice. There is an orifice in one of the legs of the tee - the leg that connects to the heater core hose. If the orifice in the tee disintigrates or is otherwise damaged, you will not have heat.

It could also be a blend door/actuator that is stuck.


Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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I had an 89' Deville and loved it . It had 225K before it was T-boned. I would install a tstat as KHE disclosed and check you heater core hoses if they are both hot after the tstat is installed.

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Thanks to all for the brainstorming. Once we get out of our deep freeze I may dig into this myself (but I may call my mechanic to see if he can do a full cooling system & heater core flush - it's due, anyway).

Brian


Brian

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Bri the Tech Guy   http://britechguy.com
britechguy@gmail.com   (540) 324-5032
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It appears that it was a combination of a thermostat that needed to be replaced (which implies to me it was sticking in the open position, but I forgot to ask about that) and that the cooling system was really sludgy. This came as a bit of a surprise given that the previous owner had been quite meticulous in maintaining virtually everything else on the car (and clearly had a new radiator put in recently) but must have never flushed the cooling system. It's also more than likely that they left in "old style change it every two years" IAT coolant in long past it's expiration date.

The system has been thoroughly flushed out, including the heater core, and refilled with Peak Global Lifetime coolant.

I now also have heat!! The cooling system should never get to this condition again.


Brian

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Bri the Tech Guy   http://britechguy.com
britechguy@gmail.com   (540) 324-5032
"If it's got you screaming, I'll help you stop!!"

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Well, I guess "no good deed goes unpunished." The combination of things that happened over the last several days has been mind-boggling.

When I had the car in for the flush they ended up having to do it twice, the second time with a cleaner (BG Cleaner) to get the sludge out, the thermostat was replaced as well. When they had the car up on the lift they found what I'd been searching for with regard to a rattling sound from the passenger side front: the folks who put in my front struts mustn't have tightened down the fasteners that hold the brake hose bracket to the strut and it had become detached and was occasionally hitting the tire and had gouged a groove in the inside sidewall.

The car went back to the strut installers on Monday night. I picked it up today and there was a bit of good news in that they did accept responsibility for the problem, repaired the bracket connection, and compensated me for a new tire.

The bad news is that something is definitely really, really wrong since the flush. Today was the first time I've taken the car out for any sort of real drive and I drove up our local interstate for about 10 miles and then back home. During that time I had the heating system set to ECON and the temperature set to 90 degrees. Here's what has occurred:

  1. I did get heat, and significant heat, but not nearly as much as I am accustomed to in my Buick when the setting is at 90 degrees.
  2. Any time you would come to a stop with the car, after approximately 10 seconds you could feel the air temperature coming from the floor heating vents drop to almost outdoor temperature.
  3. Approximately 15-20 seconds after you began moving again you would feel the heat return.

Upon my arrival home both cooling fans for the radiator were running at high speed after the car was turned off. I also have what appears to be some leakage near the radiator cap. I decided to wait to see when the fans might turn off themselves. They had not turned off after an hour, at which time I disconnected the battery. Since it’s been in the mid-30s and windy that whole time the car cannot be hot. There was no temperature warning light today and I have never had it come on since acquiring the car.

I cannot imagine what is going on here. I hope it is something that's easy to remedy but that would have been hard for the shop to know about without a long test drive. This is a shop my household has used many times before and their work has never been problematic in the past.

Addendum: It gets worse. I went outside about 45 minutes ago to reconnect the battery and decided to check the radiator - it's literally 50% empty and the surge tank is full and it's clear there's been significant coolant push out. I think I'm going to insist that the shop either send a tech to my home to take a look tow the car in themselves.

Edited by guyslp

Brian

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Bri the Tech Guy   http://britechguy.com
britechguy@gmail.com   (540) 324-5032
"If it's got you screaming, I'll help you stop!!"

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As far as the blower running continuously, - the blower control module is bad. In that vintage of car, it was separate from the blower. I think it is mounted in the HVAC case in the engine compartment.


Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Did you have pulses of warm air and cold air from the heater?

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barczy01,

Yes, I did. I now attribute that to the woefully low coolant level. I have the feeling there was an air lock and that as the air expanded it caused a lot of the coolant to be pushed out of the system.

My guess is that the "pulsing" of warm versus cold air, particularly since the cold air occurred when stopped, was secondary to insufficient pressure to send coolant to the heater core at those moments.

The shop is to take a look at the car again tomorrow. In the meantime they told me to refill the radiator and to drive the car over. Based on the way the car was acting during that test drive yesterday I don't think I've suffered any permanent engine damage, thank heavens. This whole incident is quite disturbing.

Edited by guyslp

Brian

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Bri the Tech Guy   http://britechguy.com
britechguy@gmail.com   (540) 324-5032
"If it's got you screaming, I'll help you stop!!"

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I wonder if you need a head gasket, sorry to say.

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I don't have any of the characteristic "other symptoms" of head gasket failure. The exhaust remains utterly devoid of any of the usual "coolant cloud white" that you typically get. Also there's none of the characteristic scent, either.

I pulled about a gallon of coolant out of the surge tank yesterday. I was surprised that it took only around 2 cups worth to fill up the void in the radiator at that point. I then took the car out for a short drive up the road and back. At this point the radiator was back at "half empty" but with no significant push-out into the surge tank. I then nursed over 2 of the remaining three quarts of coolant back into the the system as the car was cooling down.

The car was dropped off at the shop again last night. This morning I got a call saying they'd had the car out for a drive and afterward the level was down by approximately 1 cup. Neither they nor I can find any evidence of an external leak. They are pressure testing the system at my insistence. The latest theory is that the radiator cap has gone bad, which is possible, since the surge tank went from virtually empty to "full to overflowing" with the initial mess. I also wonder whether the replacement thermostat could be defective or "installed backwards" but that seems highly unlikely since I shouldn't get flow to the heater until the thermostat opens and if the thing were somehow installed with the wax pellet control end facing the wrong way it would never open.

I'm awaiting word on the pressure test (which I'd imagine would be bad in the case of a blown head gasket) and if that passes then a new radiator cap will be picked up on the way back from the shop.

Edited by guyslp

Brian

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Bri the Tech Guy   http://britechguy.com
britechguy@gmail.com   (540) 324-5032
"If it's got you screaming, I'll help you stop!!"

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The 4.1/4.5/4.9 engines were not known for headgasket issues. There were some cases of intake manifold gaskets leaking. If that's the case, it is a straightforward repair.

The 4.x engines were a wet sleeve design with o-rings at the top and bottom of the cylinder sleeves. The use of the GM cooling system sealer was mandatory in those engines to seal any microscopic leaks that developed in the o-rings.

The pressure test should reveal a clue to what's going on.


Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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The exact quote on today's service slip:

Pressure tested system and found a slight drop in pressure and coolant on cross member that supports radiator. Vehicle needs to be cleaned of all remaining fluid and retested for leak. Recommend radiator cap.

When I picked up the car the coolant level was slightly low, but not nearly as low as it had been for me (though they admitted that they only drove it a short distance this morning). There was clearly more coolant in the surge tank than when I had left the house last night.

I picked up a new Stant lever lock radiator cap on the way to pick up the car and installed it before leaving. I drove the ring road around town which entails highway speeds and a distance not unlike what I'd driven yesterday when the radiator went from full to half empty. Upon parking there were no leaks apparent.

After waiting about 1.5 hours I went out to check for leaks beneath the car and the situation in the radiator. Still no leaks, but good news with the radiator: It was actually more full than when I'd left the shop. It appears to have pulled some coolant back in via the overflow tube.

I attribute the coolant they found on the radiator crossmember to my own spillage while filling the radiator yesterday.

At this point I've filled the radiator to the brim and put the new radiator cap back on and washed the entire area to remove any remaining traces of coolant splashing. Now it will just be a day or two of "drive and watch."

I read about that cooling system sealer in the Service Information Manual, but have no idea if it's even available anymore. Does anyone know if it, or its aftermarket equivalent, can still be purchased and, if so, where?

Edited by guyslp

Brian

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Bri the Tech Guy   http://britechguy.com
britechguy@gmail.com   (540) 324-5032
"If it's got you screaming, I'll help you stop!!"

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You can get the pellets at any GM dealer. They are also available in aftermarket form at the chain stores such as Meijer, Walmart, etc. The product available in the stores is Bars Leaks Golden Seal. It comes in a powdered form. Do not use the powdered aluminum Bars Leaks or the Bars Leaks with the oil in it.

http://barsproducts.com/catalog/view/6-radiator-stop-leak-tablets-hdc

The last time I purchased it, I could only find it in the powdered form in a container but it is the same as the pellets, just in powdered format.


Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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4100,4.5 were known for intake manifold issues that would leak externally and or internal milkshake. 4.9 was known for head gaskets that would mix with coolant. I have installed many a head gaskets and the old style helicoils on the 4.9 but obviously the 4.9 is and was a great engine and not nearly as bad on head gaskets as the 4.6 northstar. The 3 inboard center headbolts were torqued to 85lbs, and would pull threads sometimes.

Edited by barczy01

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It appears that this issue boils down to a bad radiator cap (and the nasty coincidence that it went bad when it did and that the shop didn't catch that).

The new cap is holding all the coolant in the radiator and everything seems to be back to normal. Now it's off to the parts store to get the system sealant (although I expect that the traces of rust silt [you never get it all out] would be forced into any microscopic openings).


Brian

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Bri the Tech Guy   http://britechguy.com
britechguy@gmail.com   (540) 324-5032
"If it's got you screaming, I'll help you stop!!"

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It's rather surprising, but neither my local AutoZone or Advance Auto Parts carries the pellet version of Bars Leaks. The closest thing they both had was AlumASeal Radiator Stop Leak Powder, which is probably essentially the same thing as Bar's Leaks Powder Radiator Stop Leak & Conditioner, which I bought at Wal-Mart (which didn't carry the pellets, either).

The radiator's been dosed and I've driven about 60 miles or so this evening since, so I'll do one more check tomorrow morning to make sure the radiator level is being maintained. Based on the performance of the heat when it's set on 90 degrees, which is now infernally hot, I'm thinking life is back to "good normal."


Brian

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Bri the Tech Guy   http://britechguy.com
britechguy@gmail.com   (540) 324-5032
"If it's got you screaming, I'll help you stop!!"

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Is the sealer you bought a brown powder? If not, I wouldn't use it. The only product that is recommended is the stuff I posted the links to. The pellets are available from any GM dealer.


Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Kevin,

The stuff is a medium brown and very fine powder. While the pellets are still made there's no one who has them locally. The only thing that's available 'dry' are the two products I made reference to.

In any case, it's "too late" anyway because the Bar's Leaks powder went in yesterday. I only did this because of the weirdness after this coolant change. As a general rule, particularly on a car this age that's not leaking, I avoid coolant additives of any kind. In fact, I simply avoid additives of any kind as a general rule; I've never found them necessary when everything is working as it should (but have resorted to some as short term workarounds until proper repairs could be undertaken).

I'll probably end up doing another coolant change in a few years even though I put in Peak Global Lifetime. I think the system would benefit from one further full power flushing, although according to the terms of Peak's guarantee I have done everything I need to do to sleep easy pretty much "forever" as far as the need for a coolant change goes.

Brian

Edited by guyslp

Brian

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Bri the Tech Guy   http://britechguy.com
britechguy@gmail.com   (540) 324-5032
"If it's got you screaming, I'll help you stop!!"

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Kevin,

The stuff is a medium brown and very fine powder. While the pellets are still made there's no one who has them locally. The only thing that's available 'dry' are the two products I made reference to.

In any case, it's "too late" anyway because the Bar's Leaks powder went in yesterday. I only did this because of the weirdness after this coolant change. As a general rule, particularly on a car this age that's not leaking, I avoid coolant additives of any kind. In fact, I simply avoid additives of any kind as a general rule; I've never found them necessary when everything is working as it should (but have resorted to some as short term workarounds until proper repairs could be undertaken).

I'll probably end up doing another coolant change in a few years even though I put in Peak Global Lifetime. I think the system would benefit from one further full power flushing, although according to the terms of Peak's guarantee I have done everything I need to do to sleep easy pretty much "forever" as far as the need for a coolant change goes.

Brian

The brown powder is the same stuff as the pellets only in powdered form. On the 4.x engines it is handier since it is hard to get the pellets into the radiator without crushing them first. Bar's must have changed the packaging since I bought it last.

Once a car has had green, silicated coolant in it, the silicates plate the internals of the cooling system. Switching to an organic acid based coolant such as DexCool, the silicates deplete the corrosion inhibitors in the DexCool so that it must be changed on a two-year schedule.

The Peak lifetime coolant has an organic acid based corrosion inhibitor package in it - no idea on how it is different than Dex.


Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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As far as Bar's Leaks powder goes, I think they've succumbed to "new and improved-itis" like virtually all manufacturers do. Take a look at their cooling system products page! There are so many products, and many of them are described almost identically, that I do not find it clear at all which one should be used when. The only dry items they offer are the pellets and the stuff I bought in the tube. "Golden Seal" is no longer used to describe any of their current line.

The newest trend (and it's not all that new, actually) trend in coolants is going to versions that have lifetime corrosion inhibitor packages. It hit the heavy truck market first and some of those require the addition of a "booster" at very high mileage intervals. I hate doing coolant changes just because I don't like the feel of the stuff and because it's dangerous to animals (I'm ignoring the niche stuff here) and a PITA to dispose of. As soon as I found products available for the automotive market from major coolant manufacturers that made changing coolant a thing of the past I was on that wagon. Even thermostat technology has come so far that many manufacturers no longer have any recommended change interval for the things. I figure that if a major player like Old World is saying that you don't need to change the coolant, ever, provided you did a full flush before refilling with their lifetime formulation I believe them. Even though they limit their financial responsibility to $1K, they're well aware of the PR disaster that would have ensued had even a few users of that product been able to demonstrate that it was not offering the claimed protection. Their team of product liability lawyers certainly would have vetted the R&D data quite carefully before allowing the stuff to even go to market.

I hadn't realized that the engine in this car had a wet sleeve design. This is the same as Rolls-Royce has used since the mid-1960s. The seals on their engines are silicone, and there were some disasters with those engines and early DexCool formulations that were very high in 2EHA that attacked the seals. It wasn't limited to those engines, either, and GM found itself on the losing end of a class action lawsuit. Of course, this resulted in some significant reformulation. Since I've worked on Rolls-Royce cars I have just adamantly avoided coolant formulations that contain 2EHA. What's "funny" is the massive urban legend that's built up against long-life and lifetime coolants in some quarters of the collector car community. They insist the stuff is unsuitable for older cars and will destroy your engine. The fact that untold millions have been using the stuff (let's face it - most people will buy whatever happens to be on the shelf) and there aren't millions of older cars hemorrhaging coolant at the side of the road and lawsuits to match had ought to make a pretty strong statement. Manufacturers, whether OEM or aftermarket, are generally really, really, really conservative about making unwarranted claims that could result in legal action.

Of course, the "removal of ZDDP" (which is a reduction, not removal) being the end of old engines is just as much ado over nothing. When the ILSAC and SAE are both saying that the current service levels of motor oil for gasoline-powered engines meets or exceeds the performance characteristics of all preceding specifications I happen to believe them. They're the ones who set the standards and the testing protocols to begin with. How "friend of a friend" anecdotes morph into the weird urban legends they become, and prove to be absolutely impossible to dislodge based on factual information, I'll never understand.

But, I've digressed . . .


Brian

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Bri the Tech Guy   http://britechguy.com
britechguy@gmail.com   (540) 324-5032
"If it's got you screaming, I'll help you stop!!"

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I wonder what the difference between DexCool and the Peak lifetime coolant is?


Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Well, DexCool is an extended life (5 yr/150K mi) coolant and, as the name implies, Peak Global Lifetime is supposed to have an unlimited life corrosion inhibitor pack if the system is completely flushed prior to its being put in.

Since DexCool is a spec licensed by GM, it's not particularly likely that there will be any wide variations in formulation between the various manufacturers, though there will almost certainly be some differences.

Here are the pertinent parts of the MSDS sheets for Texaco Havoline DexCool and Peak Global Lifetime. It's pretty clear that the difference is primarily that DexCool still uses a significant percentage of 2-EH (AKA 2-EHA) and, beyond that, that there are clearly significant differences in the corrosion inhibitors. I had not realized that Peak Global Lifetime is formulated with both organic and inorganic acids.

It's beyond hopeless to get the various manufacturers to divulge their trade secrets, and that's what their exact formulations are.


Brian

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Bri the Tech Guy   http://britechguy.com
britechguy@gmail.com   (540) 324-5032
"If it's got you screaming, I'll help you stop!!"

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