Some rather scary over heating issues

[Neu]

so here is my list of symptoms that i think is a blown head gasket.


Weird heating issues. My car will heat up FAST in the morning, but it'll get about 3/4's of the way up, and quickly drop back down (thermostat sticking?)
I have over heated it somewhat badly twice so far. Bad me.
I popped the rad cap today..and a scary stream of bubbles was coming up..and the fluid level did go down slowly, but when I topped it back off it didn't go down anymore.

It cools down quickly, and when i stopped the engine and parked it at my friends place, I opened the hood up and when it started to cool, the top radiator hose actually sucked itself in, like the thermostat was closed and there was suction from the radiator.


So I drove it home a few hours after this, and it never got near halfway up the temp gauge....it's kind of baffling me.

[takza]

I THINK thermostats can only handle so much overheating before they crap out...the air might be steam? I'd put a new thermo in it and see if that fixes it.

[Neu]

Yeh, the weird thing is when I drove back to my place, it was completely normal. Didn't even get to halfway, which is where it'd usually sit, or right below it anyway.

That's the first thing I thought when all this was happening was thermostat, but when I saw the bubbles I said shit.

[danzo]

It doesn't sound like a blown head gasket - that would cause it to run hot all the time. Since it's periodic, it may be a t-stat sticking occassionally. I would change that first and go from there. Also you can replace the top rad hose with a stiffer one that won't collapse (what I did) or get one that has a spring in it. I wouldn't recommend spring hoses because after awhile the spring will corrode and chunk off, sending those chunks throughout your cooling system. I wouldn't be too worried about bubbles in the system, air can easily get trapped/leak in.

T-stats can dramatically effect the temp your car runs at. Just the other day I changed out the fuh-reakin' original t-stat in my Tercel (prolly the original hoses too). No kidding - it had a build date of 9/85 stamped on it! Anyway, it was stuck nearly closed, with about 2mm worth of clearance for coolant to flow through. This was causing the car to run cool nearly all the time. The only time the temp needle would move from the "C" mark was in traffic, when the temp would increase until the rad fan kicked on. All I did was change the t-stat, hoses, and coolant and now the needle reads just below half unless in traffic when it increases slightly until checked by the fan. Nice to have a working heater too.

Good luck and let us know what happens.

[sdoan]

Hey Chad,

Check it out carefully. The bubbles and over heating make me think head gasket so I'm a pessimist until you check it out well. Though if it never boiled water you may be OK.

The temp gauge can read too low if there is not enough water in it. If the water is below the level of the sender (at the top front of the head) the sender can't read water temp. I saw a kid wreck his father's Corvette engine this way. "The temp went up and up, and then it went down again, so I thought it was OK." Seizure - Ouch!

The wild fluctuations of the gauge can be explained by low water that sloshes up to reach the sender.

Let us know what you find. Good Luck!

[Petros]

This does not sound like a head gasket problem. The hose sucking in will happen when the engine cools if the radiator cap is not working properly. When the coolant warms the volume increases, and it has to push back the spring loaded cap into the coolant recovery container. When it cools it shrinks back, and it should suck coolant back in through the center check valve. Check the little center check valve on your rad cap, you should be able to pull it down against the spring pressure. If it is stuck, free it up and see if it will work normal. If not, or for some reason corroded closed, you need a new cap.

A quick check on the T-stat is to just remove it. If it has been more than 2-4 years since you replaced the t-stat, you might as well replace it anyway when you pull out the old one. It is easy BTW to test the T-stat, put it in a can or pot of water on the stove with thermometer and check it as it warms up. I hang it from a wire so I can pull it out and check it to verify that it actually is starting to open.

It sounds like you might have two issues, the rad cap and the T-stat. check or replace both of these and see how it behaves then. Perhaps your head gasket is okay, however you can not really tell unless you correct all the other issues first.

The upper rad hose does not need to be stiff like the lower one (where you will usually find the hoses with the wire in them). The suction of the water pump can close the lower house, so they need to be stiff to hold them open. The upper hose is on the pressure side of the pump and should not have to be stiff.

Good luck.

[gatemaster]

The upper rad hose does not need to be stiff like the lower one (where you will usually find the hoses with the wire in them). The suction of the water pump can close the lower house, so they need to be stiff to hold them open. The upper hose is on the pressure side of the pump and should not have to be stiff.

So are you saying that the lower hose should not be of the molded type but one of the bendable type with a wire inside? Cause I ussally like the molded ones as they fit better.

[Petros]

So are you saying that the lower hose should not be of the molded type but one of the bendable type with a wire inside? Cause I ussally like the molded ones as they fit better.

I agree, I like the molded ones too (I have had bad luck with the other type several times), but even the molded ones have be stiff enough not to close down if you advance the throttle. Just watch it as you advance the throttle after the T-stat is open, if the lower hose closes down, you need a new lower hose. On large engines with large water pumps they need more stiffness in the hose so they will have a wire spring inside them. Some have them molded in, which is better, they will not rust out.

Everyone knows that a good stiff lower hose is always better.

[Neu]

Everyone knows that a good stiff lower hose is always better.

BOO YA