98 Deville Engine Overheating After new Radiator Installation

[amber]

Last week I had a break job done at my local mechanic and asked them to look at the radiator as I thought I might have a small leak. (I don’t go to the local Cadillac dealer as they have a bad reputation and have done inferior work on my husbands truck. The good Caddy dealer in a ferry ride and about 40 miles away.) I thought we had a leak as in January we went across the Canadian Boarder and sat in line going a few feet every 15 minutes for about 1 1/2 hour and the temperature got up to 228 (we were monitoring the temp on the instrument panel) and there was a faint smell of antifreeze. There was never any warning light or anything displayed on the instrument panel, we were just watching the temperature.

The mechanic pressure tested the radiator and said I need to new radiator that it was leaking at the ends. They also said that it did not have Dex cool (red) in it. (I had the radiator taken in and out and recharged with coolant after having body work done 3 years ago after hitting a deer. The body shop must have put in the wrong coolant. ) We have not had to add coolant but occasionally top it off with water.

Last Wed I got the car back with the break job and new radiator filled with dex cool (red) and had been watching the temperature on the instrument control panel as we had problems with a different car after body work had been done and they did not tighten a radiator hose. I wanted to watch the Temp with the new radiator.

I watched the temp on the instrument panel when I drove and thought I smelled a fait antifreeze smell. I also noticed a small puddle of coolant about 1 cup on the garage floor under the overfill hose. On Thursday after driving the car for about 10 minutes, it got up to 230 degrees coming my drive way. I took it to the mechanic on Friday as I did not think the temperature should get up to 230 degrees. They called a few hours later and said the car was fine. They said the fans were kicking on an that it was not abnormal for the car to get up to even 240 degrees.

I drove again about 10 miles (live in the country and everything is about 10 miles away) and the temperature on the car had been around 201 and the climbed quickly from there to 240 and then 260 and I shut if off. No warning lights ever came on. I don’t think it should get that hot.

1) What is the operating temperature for a 98 Deville? (It has 70,000 miles and before the radiator replacement had run fine.)

2) How hot it "to hot"

3) Being that the car never overheated before I got the new radiator, could this be a bad radiator or could they have installed it wrong.

4) Could there be a chemical reaction between the "wrong" coolant the dex cool that can be causing this problem?

This afternoon my husband installed a new thermostat and radiator cap. Then we started it and watched the temp. The car got to over 239 degrees in about 10 minutes so I turned it off. I wanted to check what was the max temperature it should get to? Both electric fans turned on at 222 F and the temperature continued to rise. At 233 the fans kicked into high and you could hear them inside the car. I turned it off at 239 degrees.

I would appreciate answers to the above questions and any ideas. I am wondering how much I trust the mechanic when I took the car in for a break job, he put in a new radiator and now it seems to be overheating.

Thank you!

[Ranger]

240 is HOT. 260 is shut down temperature. 205 - 215 is normal.

This should not be caused by having green coolant in it, but now that it has, you still need to change it every 2 years whether you use Dex or green. If you are smelling coolant, there is an external leak somewhere. Also check the purge line to be sure it is clear and flowing coolant.

[Cadillac Jim]

If the leaks started right after a radiator job, the most likely culprits are not enough antifreeze in the coolant, leaking hoses, and the new radiator leaking.

Some garages use "universal" antifreeze that is compatible with DexCool and the old green antifreeze. This stuff is light green, but it is not your old green with silicone. You should ask the garage that filled it just exactly what he used.

The first thing that I would check would be whether you have 50% antitfreeze. A 40% mix could cause what you are seeing. The smell may be because of coolant coming out the overflow.

[Ranger]

I don't think a 40/60 mix will cause overheating. 100% water will actually cool better than a mix, but does not have any corrosion or freeze protection. That is why we have to use coolant.

[Cadillac Jim]

Ranger -- of course, you're right about water cooling better than antifreeze. The problem with some motors is that they develop steam pockets in the heads which are suppressed by 50% to 60% antifreeze. If the car does fine around town but has temperature spikes on the highway, or in heavy stop-and-go traffic, the steam bubbles can be the problem.

[amber]

I don't hink the issue is not having antifreeze. The mechanic put in what appears to be straight dex cool antifreeze. Before the new radiator it had green antifreeze put in it by the body shop.

Before they put in the new raidator I did not seem to have any problems, I went in for a break job. I thought I had a small leak but the temperature never went over 215 except the one time sitting in line at the boarder after sitting 1 1/2 it got up to 223 or maybe 228, several months back.

Now on two occasions after the new raidator it got up to 230 and then 260. I would never have even let it get above 230 but the mechanic siad that it could get to 240 w/o problems. Obviously he does not know the specs for this car. This is the same garage I have used but I have never talked to the mechanic directly, only the service rep wqho seems knowledgable. I sort of knew from just watching my temp when I drive that it was always under 220 so I have lost faith in them. Problem is I just spenty 500 on a new radiator there, and another 800 on breaks and a tie rod end.

I am surprised that no warnings or lights came on.

I took it back and left it there last night.

The anitfreeze question was more of wondering it there could be a checmical reaction making a precipiate/solid that could clog something in the cooling system that could cause the problem.

Maybe they put in a bad raidiator or put it in worong? I don't know but now I am worried that they have damaged my engine. Pretty bad to take it in for a break job and now I can't even drive it...

Thanks for the replies! It might be time to get it towed across the ferry to the dealer but even with AAA that will cost about $200.

[Ranger]

The mechanic put in what appears to be straight Dex cool antifreeze.

Perhaps that is your problem. It should be a 50/50 mix. I would think a mechanic would know better though.

[KHE]

The coolant concentration needs to be verified. If the system was filled with straight DexCool, that will be the source of the overheating. DexCool should never be added to the system straight from the container - it should be mixed 50/50 with distilled water prior to adding it to the system. The next thing to check is the cold level of the coolant in the surge tank - with the engine cold, the full level is 1-1/2 to 2-1/2 inches below the filler neck. Maybe the shop keeps overfilling the surge tank and the coolant pukes out the overflow tube??? Finally, check the purge line from the throttle body/waterpump housing area to the surge tank as mentioned in an earlier post. Disconnect the line (3/8") at the surge tank fitting and start the engine. Coolant should flow from the hose. If not, the restriction in the line needs to be removed.

[Stealth]

The coolant concentration needs to be verified. If the system was filled with straight DexCool, that will be the source of the overheating. DexCool should never be added to the system straight from the container - it should be mixed 50/50 with distilled water prior to adding it to the system. The next thing to check is the cold level of the coolant in the surge tank - with the engine cold, the full level is 1-1/2 to 2-1/2 inches below the filler neck. Maybe the shop keeps overfilling the surge tank and the coolant pukes out the overflow tube??? Finally, check the purge line from the throttle body/waterpump housing area to the surge tank as mentioned in an earlier post. Disconnect the line (3/8") at the surge tank fitting and start the engine. Coolant should flow from the hose. If not, the restriction in the line needs to be removed.

i hope to be wrong, but sounds like a headgasket breach

there are some tests you can do for an GM engine overheating

[jschunke]

If the last thing they did was change the

radiator then that is the primary suspect. Maybe

the mechanic dropped something in the hoses?

Last time I changed my radiator, forgot

to crush the pellets before placing them in the

upper radiator hose. She overheated, but gave

warning.

[Ranger]

The pellets do not need to be crushed when installed in the radiator hose. They will disintegrate fairly quickly once wet. They only need to be crushed when adding them to a radiator because of the oil cooler line inside taking up space and you can't fit the tabs in without crushing them.

[Cadillac Jim]

Coolant puddles after parking the car hot, but not overheated, seem to me to rule out a head gasket problem; that's not how they behave. You can do a quick check by sniffing the exhaust right after driving the car; if it doesn't smell funny or sweet or have a coolant smell, then you can probably forget the head gasket. What we have that indicates a leak are

• The problem began with a brake job.
• Coolant smell observed while driving.
• A small coolant puddle formed under the overflow tank when the car was parked hot.
• The fans are observed to be working as they should.
• New thermostat and radiator cap (OEM GM, not aftermarket??? This is very important!) didn't change anything.

Other things that interest me are that the behavior waiting in line for the customs agent, which originally led to the pressure test and radiator change, seems normal to me, and the behavior since seems to be a palpable coolant leak and less efficient cooling than before.

Have you checked the hoses that connect to the overflow tank? Feel the connections and see if they are wet. The puddle may come from coolant pressure bleeding down through a leak there, not from being forced through the radiator cap and overflow hose. One of them, a small hose coming from the water pump, can be kinked or loose and cause some or all of your observed problems. A quote from a post by KHE:

Disconnect the hose that leads from the water pump crossover to the surge tank at the surge tank fitting - it is on the lower portion of the surge tank. Have a helper start the car and coolant should pee out the hose. If it does not, the hose is restricted and will need to be cleaned. The surge tank is the high point of the system so any air will be purged out there. There are not any block drains so getting the engine totally purged will not be practical - that's why it is best to only drain and refill with coolant mixed 50/50. The exhause of a shop vac hose placed over the surge tank cap will help get more coolant out of the system. I removed the line on my '97 and it sprayed out.

If you decide that the car needs to go to the dealer would drive the car, even with the ferry. The behavior you cite isn't dangerous to the car. If it continues to heat up after it hits 260 F with the A/C off, just shut it down and wait for it to cool. For now you might consider going back to the mechanic that put in the radiator and brakes and tell him what you tell us, and add what we have told you. He might just add GM sealant pellets or the equivalent to the lower radiator hose, correct the antifreeze mixture, and send you on your way, or perhaps find the problem and fix it free if it's something he forgot or did.

[Stealth]

i'm NOT saying it is the headgasket, only that it sound like that is the

problem. its not easy to diag w/o standing over the engine.

one of the ways to overheat is for the very hot exhaust gases to leak

through the headgasket into the coolant system and "boil" the coolant

which in turn can "push" coolant out the overflow (per your description).

in this happening, coolant can easily be sprayed over the hot engine

components while in motion, thus the faint smell of coolant after you stop.

one can have a breach in the headgasket and NO coolant flow into the

combustion chamber and have exhaust gas going to the coolant.

the pressure differential is huge plus you got the supplement that can act

like a one way valve.

this breach often happens not in street driving but on high speed driving

or long extended idling in gear, where systems are being pushed to a bit

higher limit. piston loads and cylinder pressures are higher, to the extent

that the hot gases can breach the gasket or flow through a hairline crack.

the same principle for the WOT is also working here.

i know is only IMO, and simply going by the info provided by you.

however, the TEST KIT was only around $20 the last time i used one.

basically, it checks for CO2 in the coolant and its fairly simple to do.

should you decide to go the TEST KIT way, make sure you run the car

in the same way that you have been driving it when the overtemp

occurred before. doing the test in your driveway may or may not show

the CO2.

.............

noticed a small puddle of coolant about 1 cup on the garage floor under the overfill hose. On Thursday after driving the car for about 10 minutes, it got up to 230 degrees coming my drive way. I took it to the mechanic on Friday as I did not think the temperature should get up to 230 degrees. They called a few hours later and said the car was fine. They said the fans were kicking on an that it was not abnormal for the car to get up to even 240 degrees.

I drove again about 10 miles (live in the country and everything is about 10 miles away) and the temperature on the car had been around 201 and the climbed quickly from there to 240 and then 260 and I shut if off.

[Stealth]

duplicate .. dont know how to delete it

[Stealth]

another duplicate -

i guess i hit the save key too many times ..

how do i delete it?

[Stealth]

another?

i hope someone can delete this mess of duplicates ...

[KHE]

I wouldn't suspect a headgasket yet. It is too coincidental that the problem occured right after the radiator was replaced. The simple checks outlined above should be done first.