SC runs pretty warm after it has sat for a while?

syphon

Registered User
Hey everyone,

My '90 SC has been sitting in my backyard through most of winter. I drove it once a week for a while, then went a month without driving it, and then finally almost 2 months went without me driving it.

The weather picked up and I had some free time, so I start her up and went to make her roadworthy now.

There is a cooling issue that I'm not sure how to fix. The car warms up, but then runs a bit warmer than normal. It usually ran right at the N of norm (with the defrost on) and if the defrost was off, it'd run in between the O and the R of norm. Now, after the car warms it, it'll run right at the edge of the word Norm (right after the M). It won't overheat, but it will come close.

This is exactly what happens.

1. Start car. it slowly starts warming up.
2. Temperature jumps from cold to very warm... and does it very fast.
3. Coolant leaks out of the overlow tank. It's bubbling up so much that it leaks out of the tank when it is full.
4. The car cools down a tiny bit, but still runs warmer than usual. I havent drven it more than 10 minutes or so, so I dont know if it will overheat, but it tends to stay where it is and not get any warmer. At this time, the coolant overflow tank recedes down.

What do you guys think is the issue here? Do you think my thermostat is faulty? I just replaced it less than a year ago. Any other ideas? Thanks!
 
Wow! I've been trying to make that post for weeks and keep getting mysql errors! I'm glad it finally went through.

I should also append that the coolant level is fine. The defroster is on at all times... the air stays cold even when the temp is way up high. Only after the coolant level recedes does the air start to warm up.
 
Thats odd????

I wonder if you don't have some sort of partial blockage in your heater core :confused: ...just a wild guess...don't use the heater much down here.

Rick in FL :cool:
 
could be headgasket they will act that way but check thermostat first and when it cools down check radiator and make sure its full and check for coolant in the oil
 
Good point!

Yea you may wanna check the thermostat that never even occured to me because it stays so warm here I just eliminated mine :D ....Good thinkin there "R"...

Rick in FL :cool:
 
I'm thinking (and praying) that it's not the headgasket. The problem occured almost too suddenly I think.

The car sat for a long time. I would take it out every other weekend and drive it all weekend, and it would run wonderfully. Then it sat about a month without driving, and it exhibited the problem immediately. I'm hoping a coolant flush and new t-stat will help me.
 
Ok, I drained the coolant, changed out the thermostat, and changed the oil.

Good news is that the oil looked fine, no sign of HG failure.

I'm letting the silicone stuff dry overnight before I flush the cooling system, so we'll see how it runs tomorrow.
 
From what you say, I think it's a sticky thermostat, too - and it's an easier change than a head gasket. So, changing that first was the right thing to do in my book. Good luck with it.

But, you don't necessarily get coolant in the oil with a blown headgasket. You can, but you might not. I've blown many headgaskets that caused the engine to overheat, and never once did I have coolant in the oil.

When you say it was bubbling, did it have tiny air bubbles or large air bubbles or just significant coolant flow?
 
No bubbles... I meant to say "it was overflowing out of the coolant resevoir". maybe "bubbling" was a poor choice of words.
 
syphon said:
It usually ran right at the N of norm (with the defrost on) and if the defrost was off, it'd run in between the O and the R of norm. Now, after the car warms it, it'll run right at the edge of the word Norm (right after the M). It won't overheat, but it will come close.
Thanks!

When you push the defrost the low speed fan turns on, so could use it if you when you are uncomfortable with temp, as you experienced a lower temp.
Also, you may want to checkout www.dccontrol.com it helped my engine temp from jumping up and down, if other solutions don't work out. But it has to be hooked up in way that it does not turn on in conjunction with high speed fan, or fan will burn out.
 
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my cougar did the same thing with where the coolant leaked, the car also overheated all the time. i also noticed that the car performance was horrible. i hate to say this to you but it was the head gaskets for me.
 
rlong said:
could be headgasket they will act that way but check thermostat first and when it cools down check radiator and make sure its full and check for coolant in the oil

That is exactly what mine did before the HG's took a dump. I would have to say the HG's are toast.
 
Wow, you guys bumped an ancient thread.

Also, the car turned out to be fine. I dont know why, but after sitting for a month or so, it ran beautifully.
 
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