3400 Common over heating issues?

[Tinkles]

My little bro has a 99 Olds Alero(63k miles on the clock) with a 3400 and is over heating quite regularly. I have changed the T-stat, there are no visible leaks, no coolant in the oil, no puddles, no exhaust smoke at all. We dropped it off at a "garage" and they did was bleed the air out of the system, not find out how it got in there in the 1st place. Im usually pretty decent with diagnosing problems, but im clueless with this.

Are there any "common" cooling issues? Any ideas?

[Superdave]

heater core is one regular way air can get in the system.

get some of the UV dye at the parts store and a UV flashlight, run that through the coolant system for a while and you should be able to find the leak.


Welcome to 60degree!

[shwgidy]

Check the oil for coolant milkshake.

[Tinkles]

heater core is one regular way air can get in the system.

get some of the UV dye at the parts store and a UV flashlight, run that through the coolant system for a while and you should be able to find the leak.

I'll try that, thanks.

Check the oil for coolant milkshake.

I already said the is no coolant in the oil.

[60dgrzbelow0]

Generally... air trapped in the cooling system that migrates into the water pump housing immediately diminishes the ability to move the coolant around, since the water pump impeller is designed to act against the incompressible fluid. The best way to solve this problem is to find either the actual "Bleeder Valve(s)" on your engine or the highest point in the cooling system where the air bubbles can amass that you can let the air out via an un-clamped hose. Before you begin by starting the engine in the driveway with the hood up and a garden hose handy... mix the water in a 50/50 ratio with the kind of new anti-freeze that your car manufacturer recommends. Avoid "mixing your colors" (say...orange with green) here as you may have issues later on that are unpleasant if their chemistry is incompatible. Then, with the radiator cap in place and tight and the coolant overrun tank filled to the proper level, start and run the engine at idle until you begin to see your thermostat rise. Then, when the engine is nice and warm...just open the bleeder valve(s) that are probably located somewhere along the line where the heater hose(s) come off the water pump manifold. Your Haynes or Shop Manual will be your guide to find them. Do this long enough to sort of "Burp the Baby" of all of the air pockets and let this go on until you see a steady stream of coolant coming out. Then just snug the valve(s) closed and check your dash panel temp gauge for any changes that show the temperatures are lowering and then take the car for a 10 minute drive to see if the engine temp continues to behave. When you get back in the driveway... let the car cool down and top off your radiator and coolant tank at the "COLD" level and look over the engine for any coolant leaks from the bleeder valves. This will almost always solve the problem. Please dispose of any extra anti-freeze in a responsible manner, as "PEG" (Poly-Ethelyne-Glycol) has an attractive odour and sweet taste that animals enjoy lapping or drinking and it invariably paralyses and kills them...mostly local dogs... who might wander up after your job is done and get into trouble if they find the stuff.

[Tinkles]

I already know how to bleed a cooling system. My concern is HOW did the air get in there in the 1st place. The car is losing coolant w/o any signs of external or internal leaks.

[19Cutlass94]

I know on my car, the WP gasket leaks a little, but theres never any dripping. Its leaks slow enough that its just steam. but it leaks enough that I loose coolant over time. How much coolant are you looking in what period of time?

[Tinkles]

It'll empty the overflow tank in a 20mile trip.

[asylummotorsports]

Pull the spark plugs.

If you have a REALLY clean one, you have found where the coolant is going.

As well you may want to check the pressure cap.

[3400-95-Modified]

It'll empty the overflow tank in a 20mile trip.

Then you are burning it in the cylinders via a leak on your headgaskets which is also causing your overheating issue, OR you are leaking into the motor and mixing with the oil.

[60dgrzbelow0]

Then you are burning it in the cylinders via a leak on your headgaskets which is also causing your overheating issue, OR you are leaking into the motor and mixing with the oil.

... and A/F PEG in the motor oil is very nasty and corrosive on Babbitt bearing surfaces...

[Tbay99Venture]

Goo

Here's an example of what you find if the leak worsens.

http://www.youtube.com/watch?v=VImQZDfxAyg&feature=related

Not that I know these guys or anything, just was looking around on the subject.

[Tinkles]

I already said there is no signs of it burning coolant or coolant mixing with engine oil. Anyways the damn thing has been dropped off at a garage with the proper diagnostic tools.

[3400-95-Modified]

I already said there is no signs of it burning coolant or coolant mixing with engine oil.

Ok, I can understand the lack of evidence for mixing with the oil and claiming thats not the issue, but what proof do you have to say its not getting burnt?

There are three places coolant can go when your "using" it...

1) The Ground
2) Oil
3) Cylinders

You've already ruled out the oil since its NOT brown and not gaining capacity... and you've already said there are no puddles or visible leaks. So that leaves ONE more route... and that does NOT always result in exhaust smoke, it all depends on how severe the leak is.

This isn't magic, it has to go somewhere, so your missing a big leak somewhere, or you just don't want to take our advice about it possibly burning it.

I'm curious to see what the "Mechanics with the proper diagnostic tools" have to say about your issue... Please inform us when you know. IIRC you've already brought it there once and they simply bled the air out of the system... Where were their tools then?

Sorry to come across like an ass, but your asking for our advice and then you beat down every possible solution we present, but at the same time you're asking because you don't know the solution to the problem right?!!? At least give our advice a chance and re-explore the avenue's we are presenting to you, because obviously something is being over looked.

I'm really sticking to leaking headgasket though. You have two of the most common symptoms of a bad headgasket, repetitive overheating and coolant loss.

[Tbay99Venture]

Head gasket fun

I just got done replacing the head gaskets (3.4L) going on 3 weeks ago. I've done a few of them on different cars now and this was a small leak but at least was making white exhaust. The plugs really didn't have any differences between 'em but the compression reading told the story.

My most spectacular fail was on a Toyota inline 6 with the alloy head. My wife and I had stopped to get a video tape and by the time we got back in there was enough water in the cylinder to jolt the starter to a standstill. With another friend we got it push started and left with a trail like a steam locomotive. Still ran w/o problems after a re-gasket.