QUICK QUESTION!?!?!

[davedog]

Hey guys, I need a quick answer to a question....I'm changing my engine coolent in my 92 eldo with the 4.9 engine. Guru suggested I might change my radiator cap if it looked like it was in rough shape....it looks pretty bad so I went to autozone and they looked up my car and handed me what I assumed was the right cap. I got home and was reading my manual which says it should be a 15lb radiator cap, the one the gave me is a 16lb. I called back and they said this doesn't matter, and thats what their computer says to use too. Is a 16lb ok when the book says 15lb????

Thanks!!!!!

-dave

[Ranger]

I wouldn't swear to it but I don't think 1 lb. will make too much of a difference.

[davedog]

i called two auto parts stores and they both said all the carried for my car was 16lb radiator caps, and the both said it would be fine, I'm just not sure if they were trying to make a sale or if tis is true....thanks for your input ranger.....anyone else know for sure?

P.S. The manual says after draining the old coolernt out to fill it back up with water, and run the engine until the themostat opens, then shut of the engine, drain again, and to repeat until the water comes out clean.....HOW DO I KNOW WHEN THE THERMOSTAT IS "OPEN"??????

[Bob D]

i called two auto parts stores and they both said all the carried for my car was 16lb radiator caps, and the both said it would be fine, I'm just not sure if they were trying to make a sale or if tis is true....thanks for your input ranger.....anyone else know for sure?

It will be ok in the short term..only increasing the boiling point a bit from 260f @50/50 fluid ratio...

But...If more was really better here, why didn't the cooling system design engineers go with 16 lbs?

If it was designed for 15lbs, I'd try to go with 15lbs.

[davedog]

thanks bob D....sorry I posted this late: anyone know

P.S. The manual says after draining the old coolernt out to fill it back up with water, and run the engine until the themostat opens, then shut of the engine, drain again, and to repeat until the water comes out clean.....HOW DO I KNOW WHEN THE THERMOSTAT IS "OPEN"??????

[TDK]

In the 4.9, you can leave the radiator cap off and observe the water in the top of radiator.

When the water begins to move, then the thermostat is open and circulating the water through the radiator.

Up to that point, the thermostat is closed and circulating water only within the engine and heater core.

I suppose the hoses to/from would get hot when the thermostat opens - if you left the cap on. But since its only to flush, the cap can remain off for those few minutes.

[Bob D]

thanks bob D....sorry I posted this late: anyone know

P.S. The manual says after draining the old coolernt out to fill it back up with water, and run the engine until the themostat opens, then shut of the engine, drain again, and to repeat until the water comes out clean.....HOW DO I KNOW WHEN THE THERMOSTAT IS "OPEN"??????

Fill it up to the mark, and fire it up. When the standing coolant suddenly ‘changes state’ i.e., begins moving (you can see the flow) and immediately warms, you’ll know that thermostat has opened.

[adallak]

dave,

1 lb difference is not going to blow your cooling system, but what was wronfg with original cap? Was the radiator full up to the neck when you removed the cap (cold engine of course)? If it was full your cap was most likely fine.

When the stat opens (190-200 deg.) th eupper radiator hose becomes really hot and hard (hmmm... ). Another way to make sure the stat is ok watching the temp on the DIC at certain point (190-200) it will drop sharply to say, 170 and then continue to go up. It happens when stat opens and cold volume of coolant mixes with hot one.

Boy, you killed everybody with questions just do it!

[davedog]

THANKS SO MCUH EVERYBODY!!! You guys rock. It all makes sense now.

Adallak: Before when I pulled the cap I could see no coolant. Even though the overflow tank was filled.

Thats why (with Guru's help) I was thinking the cap should be replaced.

The old cap has all kinds of gunk up in it...I washed it but is that enough?

Oh, and I took the overflow tank out and cleaned it....it had all kinds of gunk in the bottom of it, AND the hose that goes (hey that rhymes ) between the overflow tank and the radiator was clogged up. I unclogged it, cleaned both real good and reinstalled it.....do you think this was the problem, or the radiator cap? Hmmmm....

Thanks so much for helping a coolant noobie!

-dave

P.S. the engine has never overheated

[Bob D]

THANKS SO MCUH EVERYBODY!!! You guys rock. It all makes sense now.

Adallak: Before when I pulled the cap I could see no coolant. Even though the overflow tank was filled.

Thats why (with Guru's help) I was thinking the cap should be replaced.

The old cap has all kinds of gunk up in it...I washed it but is that enough?

Oh, and I took the overflow tank out and cleaned it....it had all kinds of gunk in the bottom of it, AND the hose that goes (hey that rhymes ) between the overflow tank and the radiator was clogged up. I unclogged it, cleaned both real good and reinstalled it.....do you think this was the problem, or the radiator cap? Hmmmm....

Thanks so much for helping a coolant noobie!

-dave

P.S. the engine has never overheated

Dave, describe the "gunk" that was A. "Up in the radiator cap", and B. clogging the hoses.

Try and describe the color and consistency. I.e thick, gooey, frothy..you get it..

Just curious..

[adallak]

Dave,

You are doing ok. BTW you must have a leak/leaks if the radiator was half empty. Watch the level carefully for a week or so both in the surge tank and the radiator itself when it is cold.

[davedog]

THANKS SO MCUH EVERYBODY!!!         You guys rock. It all makes sense now.

Adallak: Before when I pulled the cap I could see no coolant. Even though the overflow tank was filled.

Thats why (with Guru's help) I was thinking the cap should be replaced.

The old cap has all kinds of gunk up in it...I washed it but is that enough?

Oh, and I took the overflow tank out and cleaned it....it had all kinds of gunk in the bottom of it, AND the hose that goes (hey that rhymes  ) between the overflow tank and the radiator was clogged up. I unclogged it, cleaned both real good and reinstalled it.....do you think this was the problem, or the radiator cap? Hmmmm....

Thanks so much for helping a coolant noobie!

-dave

P.S. the engine has never overheated

Dave, describe the "gunk" that was A. "Up in the radiator cap", and B. clogging the hoses.

Try and describe the color and consistency. I.e thick, gooey, frothy..you get it..

Just curious..

kind of a greyish color, wet-mud like consistancy. Nasty stuff.....looks like it should have been in a swap, not my car. The radiator itself looks clean, just round and up in the cap, and a lot in the overflow tank, and enough to clog the hose.

I've never seen anything come out both, so If it's a leak it has to be slow (haven't added coolent since I bought it a year ago....never added coolant o the radiator itself.)

I'm thinkin, since the coolant in the overflow tank had no where to go (thet hose was COMPLETLT clogged), it just evaperated over time??? And so the radiator itslef was alittle low since it wasn't circulating with the overflow tank????? Am I understnading this? LOL

-dave

[Ranger]

Dave,

I was thinking that the "gunk" was sealant tabs but the color is wrong. It is muddy looking not greyish. At any rate, I think you found and cured your problem. If you cleaned out the hose, tank and the cap, just refiled it and keep an eye on it. After a few days, with the engine cold, remove the radiator cap and see if the radiator is still full. It should be right up to the base of the filler neck where the radiator cap seats.

[adallak]

I'm thinkin, since the coolant in the overflow tank had no where to go (thet hose was COMPLETLT clogged), it just evaperated over time??? And so the radiator itslef was alittle low since it wasn't circulating with the overflow tank????? Am I understnading this? LOL

The autopsy will tell Just keep an eye on it. BTW coolant level may need a couple more adjustments since the system won't get rid of the air at once.

Check the level in the radiator in a couple of days and add. Repeat it once or twice again to make sure the system purged the air. If you keep adding coolant ... you have a leak. Hopefully external one (cracked end tan is very likely).

[davedog]

THIS SO SO FREAKIN' AWESOME!!!!

The overflow tank is actually doing it's job now....I put the radiator cap back on (the old one) and after a few minutes it sucked some coolant out, the pushed some back in!!!! It NEVER did that before. It's pretty much settled to one level now, but I'll keep an eye on it over the next couple days.

YOU GUYS ROCK!

THANKS!!!!!

[Ranger]

If there is any air in the system, it will get trapped at the neck (high point) and should get push out into the overflow tank as the coolant expands. Then as the coolant cools and contracts in volumn (if the cap is working correctly) it will draw coolant back in from the tank. After expelling any air that may be in the system the level should stay the same if all is well.

[davedog]

If there is any air in the system, it will get trapped at the neck (high point) and should get push out into the overflow tank as the coolant expands. Then as the coolant cools and contracts in volumn (if the cap is working correctly) it will draw coolant back in from the tank. After expelling any air that may be in the system the level should stay the same if all is well.

YUP!!!

Thats exactly what was happening for the first few minutes! Lots of bubbling and churning in the overflow tank...then it settled down. So I guess the old cap is working right after all.

Before It never did anything, and it stayed at the EXACT same level inthe overflow tank hot and cold!

[davedog]

The 16 PSI cap is fine.  Most current engines have migrated to an 18 PSI cap to add some cushion to the boiling point of a 15 PSI cap.  I wouldn't hesitate at all to use the new 16 PSI cap.  Likely the seal on your old cap is getting worn anyway.

The main thing is...does the new cap you bought have the little silver disc in the middle of the part of the cap that goes into the radiator??  It must have that 'drop valve" to be the correct cap.

If you filled the system with plain water and then drained it likely you trapped some plain water in the system...so...that extra water dilutes the 50/50 premix that you filled with so that it is no longer 50/50.  You should find someone with a refractometer to check the coolant concentration in the radiator and see what it is.  You may need to drain some out and top off with pure antifreeze to get the mix back to 50/50.  Don't trust the hydrometer style testers...the ones with the myriad of floating balls.  Find a shop with a hydrometer to check.  You can pull a little coolant out of the rad when it is cold and ask them to test it.  You want to check what is in the system after it has mixed up...not what is in the reservior. 

You might notice the reservior level drop slightly the next few days.  That would be normal as any air is purged from the system.  Check the rad itself when cold for level to make sure it is refilling at cool down.  Top off the reservior after a few days and leave it alone.

thanks Guru!!!!

Hopefully after a few days everything will be normal now, and I won't have to investigate leaks n' such further. I've never seen a leak, but who knows!?!

Once the engine cools down I'll put the new cap on, thanks for clearing that up Guru. The old one seems to be doing it's job now that everything is unclogged, but your right Guru, it does look pretty worn. I guess I would be to if i had been holding HOT liquids at bay for about 13 years! And yes Guru, it has the little metal disk at the end of a springy thing....looks just like my old one.

Again thanks everyone.

Now I should go to bed cause I'm getting paranoid. I was doing some research about where else the coolant could have gone if it was a leak...and I came across head gaskets! Yuck! Sounds scary. I even found some info that said that can cause smelly exuast? Mine has always smelled about 25% of the time since I got it. Still though, if it is leaking, it has to be SLOW, haven't checked it in over a year.

But then again, it's probably fine, and I'm just sleepy and over analyzing everything...

[davedog]

CRAP! THIS MAY NOT BE GOOD:

When I first finished up I let my car idle in the driveway while I cleaned up. When I put i back I of course noticed alot of water under where the engine had been, no big deal, I made a mess with the hose and all the water, and flushing, and reflushing, but I also noticed two small wet spots back under where each of the dual exaust pipes end???? I wnet back inside my garage and sure enough there wher a couple of drops under each pipe, and the insides were most. I sure have never noticed this before! I took it out for a spin on the highway, for some "spirited" driving. Came back, everything was normal, and dry. Had to go out again for something, and then a third time, dry at each stop, and then on this last trip home I happened to rev it up a few times once I was parked, up to just under 3k RPM, but each time it reached just under 3k rpm it made a strange little noise, hard to decribe.

Then I went around back, insided of pipes were moist again! Please tell me this is not what i think it is?

[Ranger]

I wouldn't panick just yet. Moisture is a byproduct of combustion. A little moisture in the pipes is normal. The colder it is outside, the colder the pipes are and the more moisture you'll see. Keep an eye on the coolant level. If it starts going down, then worry.