Had an interesting problem with my radiator today...

[KingNothing]

Car: 1995 Geo Prizm, 120,000 miles

I was driving and I smelled something burning. 5 minutes later when I got to my destination, there was antifreeze all over the engine compartment near the overflow container. I wasn't far from home so I drove with the heater all the way up and the fan all the way on in ~40 degree weather. The temp was fine whenever I was moving, when I stopped it would climb rapidly.

I had my thermostat replaced last week because for a few weeks prior it would take 15 minutes before the idle went down and the temperature gauge went up to normal. Replacing the thermostat fixed that problem.

The interesting bit is there's black stuff all over a section of the surface of my radiator on the engine side. I don't remember it being there before, but I don't know for sure. It rubs off and feels like engine grime.

I poured more coolant in, no visible leaks, and I started it up, no visible spraying.

Since the coolant spray is near the overflow container, it would seem that the coolant exited the system through the overflow hose. I don't get why though. I'm taking it to a shop tomorrow or maybe Friday, but anyone have any ideas in the meantime?

 

[iamwiz82]

Where the the pressure valve on your car? Is it on the coolant tank?

 

[Kalvin00]

.

 

[KingNothing]

Originally posted by: iamwiz82
Where the the pressure valve on your car? Is it on the coolant tank?

The shop manual says "the engine utilizes a pressurized coolant-forced circulation system which includes a themrostat equipped with a bypass valve mounted on the thermostat housing."

Is that what you're talking about?

 

[miniMUNCH]

thermostat f'ed up...again causing overheating. Or you have a partial plug in the coolant system downstream of the overflow tank.

I'll bet it's your thermostat...the way part failures work, failure probability is highest during the "break in" period or towards the end of like (i.e. 100,000 miles of service).

 

[BentValve]

Have you been driving it fine for a few days since having the T-Stat replaced?

If you have driven it a significant amount since the repair under multiple load conditions then id have to agree with the bad T-Stat theory otherwise my guesses would be the following starting with the least likely.

A. The mechanic did not bleed out the cooling system completely.
B. The mechanic installed the T-Stat backwards.
C. The mechanic did not bleed out the system completely which resulted in a very low coolant level..
enough to cause air behind the thermostat as hot air does not open up thermostats.


But really that is just a stab in the dark without actually looking at the car as there are a plethora of other reasons why the car could have splilled some coolant.

 

[KingNothing]

Originally posted by: BentValve
Have you been driving it fine for a few days since having the T-Stat replaced?

If you have driven it a significant amount since the repair under multiple load conditions then id have to agree with the bad T-Stat theory otherwise my guesses would be the following starting with the least likely.

A. The mechanic did not bleed out the cooling system completely.
B. The mechanic installed the T-Stat backwards.
C. The mechanic did not bleed out the system completely which resulted in a very low coolant level..
enough to cause air behind the thermostat as hot air does not open up thermostats.

But really that is just a stab in the dark without actually looking at the car as there are a plethora of other reasons why the car could have splilled some coolant.

I have driven it a significant amount. It seemed fine...the idle dropped to normal within a few minutes. I thought that the hot air coming from the heater seemed warmer after the thermostat was replaced, but I don't know for sure.

Any thoughts on the black grime on the radiator? I don't know at all when that showed up, so it could be unrelated. It's a fairly large patch though.

 

[BentValve]

Really that is an almost impossible question to answer without actually looking at the vehicle..take it to your mechanic and tell him what you have told us.
Hopefully he is honest so that you can really know what happened...its entirely possible that he will just take care of it and tell you it was nothing.

 

[KingNothing]

It turns out a guy I knew several years ago is working at a Brake Masters as an auto mechanic, so that's where the thermostat was replaced. He just got a 2-year automotive repair degree from Metro. I trust him, dunno if he actually knows anything, but I trust him.

 

[Injury]

To find out what the problem is, drive around for an hour, then immediately open it up and look inside. If you see stuff in there, then it's broken. If you can't see anything, then it's probably because you opened up your radiator while it was hot.











Just kidding. Don't do this.

 

[BentValve]

lol, well thats cool and its especially good that you trust hime but just so you know that saying "He just got a 2 year automotive repair degree" and saying that it means something is about equvalent to saying "I can flip on a PC, gues I can start writing software now."


Good Luck with it.

 

[MisterJackson]

Could be a pinhole puncture in a hose. With enough pressure it can douse the engine compartment w/ antifreeze. That would explain the "No visible leaks or spraying".

I'll send you my bill if I turn out to be right. If I'm wrong then all I can say is "Why in the hell are you asking me for advice?!?!".

 

[TitanDiddly]

Take it back to the dude who put in the ne thermostat.

 

[KingNothing]

Yeah, it's going back there either tomorrow or the day after. They said they'd do a pressure check for free. Guess we'll find out...