Its overheating again...

[xtremerevolution]

I drained the coolant and re-filled it with a 50-50 mix when I did the lim gasket at around 186k. its at 204k now. I did not replace the thermostat at that time, and its been at least 40k since its been there. It was a 180 degree thermostat.

 

The reservior is not overflowing. quite the contrary, i'm LOSING coolant at a very slow rate. I just changed my oil on saturday after 6500 miles (was busy, I know) and it was typically dark, but not foggy or otherwise showing evidence of head gasket failure.

 

Today I was driving with the A/C on full blast in 91 degree stop and go traffic and the needle was sticking right under the 3/4 mark, but never went above.

 

When I popped the hood, both fans were running. No traces of coolant leaks ever seen under the car.

 

Any ideas? Thermostat stuck? clogged radiator?

 

I'm leaning toward thermostat since it would rise above that point before, but then creep down back to the half mark. This time it didn't creep back down.

[1990lumina]

Start with the cheaper item - I'd try a thermostat first too and bleed the system real well.

 

My Lumina has a 195º t-stat in it and it'll never go above half on the guage - it normally sits around 3/8 on the guage.

 

If you put a new t-stat in and you are still heating it's possible your rad isn't as effective as it once was.

 

However neither of these two parts explain your coolant loss unless you can see where it is leaking external or burning off on something hot.

[xtremerevolution]

well the coolant loss is very small. its the amount between the low mark and the hot mark in the overflow tank in 5,000 miles.

 

If I decide to drain and clean out my cooling system with a coolant flush solution, how do I dispose of the old coolant?

[Night Fury]

well the coolant loss is very small. its the amount between the low mark and the hot mark in the overflow tank in 5,000 miles.

 

If I decide to drain and clean out my cooling system with a coolant flush solution, how do I dispose of the old coolant?

 

In typical classic w-body style:

 

In teh grass........

[Regal_GS_1989]

well the coolant loss is very small. its the amount between the low mark and the hot mark in the overflow tank in 5,000 miles.

 

If I decide to drain and clean out my cooling system with a coolant flush solution, how do I dispose of the old coolant?

I'm sure that it's probably not the best way...but i dump mine in with my used oil, then i dump my used oil in the big recycling collection containers at the garbage dump.

[Crazy K]

coolant should not be mixed with waste oil...

 

if youy look on the bottle, it says it can be dumped into a treated sewage system (not storm drain), aka down the toilet, if you don;t have a septic tank.

[tornado_735]

When I flushed the reservoir in my GP I just dumped it in the grass. The grass is now dead I don't really give a crap though, because it's the grass 'maintained' by the apartment complex I'm leaving in a month anyway.

 

I flushed the radiator in my Jeep out in a car wash a couple of weeks ago. I figured it was just as good a place as any, since all the soap and wax and crap goes down the drain there anyway.

[xtremerevolution]

So I'm thinking the thermostat is indeed sticking. Saturday it was hot as balls, around 92 degrees out here. I drove the whole day with AC on max and never went past 2 hairs over the half mark. I think even that is a bit high for a 180 degree t-stat, but whatever. Sunday it was the same weather, and it climbed to the 3/4 mark while sitting in a parking lot. I shut it down, came back an hour later, and ran it again for half an hour with A/C on max in that same parking lot and it never went over the half mark.

[tornado_735]

So I'm thinking the thermostat is indeed sticking. Saturday it was hot as balls, around 92 degrees out here. I drove the whole day with AC on max and never went past 2 hairs over the half mark. I think even that is a bit high for a 180 degree t-stat, but whatever. Sunday it was the same weather, and it climbed to the 3/4 mark while sitting in a parking lot. I shut it down, came back an hour later, and ran it again for half an hour with A/C on max in that same parking lot and it never went over the half mark.

 

Sound's about right. Good thing T-Stats are like $6 bucks.

[xtremerevolution]

So I'm thinking the thermostat is indeed sticking. Saturday it was hot as balls, around 92 degrees out here. I drove the whole day with AC on max and never went past 2 hairs over the half mark. I think even that is a bit high for a 180 degree t-stat, but whatever. Sunday it was the same weather, and it climbed to the 3/4 mark while sitting in a parking lot. I shut it down, came back an hour later, and ran it again for half an hour with A/C on max in that same parking lot and it never went over the half mark.

 

Sound's about right. Good thing T-Stats are like $6 bucks.

 

Even better is that I already have one in the back of the regal ready to put in! Just need to drill a 1/16" hole through the center to make it easier to bleed the air.

[tornado_735]

So I'm thinking the thermostat is indeed sticking. Saturday it was hot as balls, around 92 degrees out here. I drove the whole day with AC on max and never went past 2 hairs over the half mark. I think even that is a bit high for a 180 degree t-stat, but whatever. Sunday it was the same weather, and it climbed to the 3/4 mark while sitting in a parking lot. I shut it down, came back an hour later, and ran it again for half an hour with A/C on max in that same parking lot and it never went over the half mark.

 

Sound's about right. Good thing T-Stats are like $6 bucks.

 

Even better is that I already have one in the back of the regal ready to put in! Just need to drill a 1/16" hole through the center to make it easier to bleed the air.

[xtremerevolution]

so today the needle was passing even the 3/4 mark while parked in 95 degree weather while parked, by about one hair's mark.

 

I checked under the hood and the level in the washer bottle was an entire inch and a half too high.

 

I get back in the car, keep the engine revved for a while, and watch the temp go down to midway between the half and 3/4 mark. I look back under the hood and the level is at 'cold' on the reservior.

 

I think wtf, and notice that the underside of the radiator overflow hose was wet...with coolant.

 

Go figure, the hose was leaking so the car was sucking back air while cooling down.

 

I replaced the radiator cap with a quick pressure release one, replaced the hose and the clamps, and topped off the radiator twice. It hasn't gone more than a hair over the halfway mark since then. I'm sure there's more air in the system, but at least now its not getting as hot. I'm still planning to replace the thermostat tomorrow.

 

Currently 95 degrees out, A/C on max sitting in stop and go traffic, solid at the half mark.