Well, removed the t-stat and car is still running hot...

[5spd GT]

I finally got around to removing the t-stat completely and my car still runs hot. It doesn't peak as high and it takes quite a bit longer to warm up compared to with the 195* napa t-stat but it still runs hot

It will spike up pretty quickly (like before) and then drop down like the t-stat opened up and keep doing that over and over

What the ?

Any thoughts appreciated?

Headgasket blown? Block cracked? Etc?

Thanks

 

[Michael Yount]

Are you losing coolant?

If you're not losing coolant, and it's heating up in this weather with plenty of cold air going across the rad -- then my first guesses would be that either something is wrong with the radiator (can't reject the heat) or something is really wrong internally causing the motor to produce so much heat that the rad can't reject it. If it were the latter, you'd likely have other symptoms - drivability, noises, etc.

Did the problem just show up one day all at once -- or was it a gradual thing? What kind of coolant do you run? Have you done anything recently to the cooling system - other than remove the t'sat of course?

What are you basing the 'it's running hot' on -- what kind of gauge/sender/sensor?

 

[04sleeper]

David,

Is this on your factory gauge?

 

[timewarped1972]

Are you losing coolant?

If you're not losing coolant, and it's heating up in this weather with plenty of cold air going across the rad -- then my first guesses would be that either something is wrong with the radiator (can't reject the heat) or something is really wrong internally causing the motor to produce so much heat that the rad can't reject it. If it were the latter, you'd likely have other symptoms - drivability, noises, etc.

Did the problem just show up one day all at once -- or was it a gradual thing? What kind of coolant do you run? Have you done anything recently to the cooling system - other than remove the t'sat of course?

What are you basing the 'it's running hot' on -- what kind of gauge/sender/sensor?

i agree, check all of that, have you tried flushing the cooling system to see if theres alot of gunk in it?? could just be your radiator especially if its a stock one. check your oil, thats doesn't always show a blown head gasket but sometimes it does, do you have any white smoke coming from your exaust?? check the basic things first before you assume it's something major..
also, when the cars running, being you now have no t-stat, you should be able to take off the radiator cap ( before it's to hot ofcourse) shine a flash light in there and see if theres coolant circulating through the radiator as well..
edit.....i just saw your sig you have an electric fan and a griffin radiator correct?? how olds the water pump??

 

[5spd GT]

Yes, factory guage but it has never given me reason to not believe it.

It started happeneing all at once.

I had a big overheating problem one time in Little Rock about 5-6 weeks ago and it actually overheated, I know. Coolant was coming out of the overflow tube and I heard a whistling noise in the engine bay (by the engine). That night and ever since then the car ran like it had always had until a week or so ago.

I have removed the cap (by hand) after it "shows" that it is hot and it spews coolant and smokes and all but I'm not for sure how much spewing is supposed to come out?

I do know I noticed detonating and all when the guage shows "hot"...? Haven't noticed so much lately.

I haven't noticed any noises or driveability or oil pressure problems...

Thanks for the replies guys

Edit: I don't see why the radiator wouldn't reject the heat...and my coolant and all seems fine. I don't think any of it is gunked up.

 

[04sleeper]

Does the oil have any water in it?

Does the water have any oil in it?

Does the radiator smell like exhaust or have anything black in it?

Do you still have the stock fan clutch?

 

[5spd GT]

Haven't checked oil...

Haven't seen any oil...

Haven't noticed any smells besides coolant (when it shows hot)

Black Magic Electric Fan but on the highway it doesn't effect it with my car and radiator.

 

[timewarped1972]

you said you may have heard a hissing noise at one time, like a steam leak.......have you looked over the freeze plugs?? sounds like your not leaking any coolant per say, but you have a steam leak some where, which could come from a zillion places , either that, or for some reason your fan is not doing a good job at slow speeds......
was it also not you that replaced your intake manifold awhile back??.......maybe that was another person.....

 

[04sleeper]

Hmmmm. Well I know your radiator is fairly new so I wouldn't think it to be the culprit. I have heard many bad things about Black Magic fans though. But you said it doesn't change anything and that it overheats on the highway?

I would vote either a blown head/intake gasket or bad radiator.

Is there any smoke coming out of your exhaust?

 

[troyGT03]

when you remove the t-stat the coolant flows faster and doesnt have time to dissipate the heat from the engine. water/coolant needs to move slower to soak heat from the engine components and then cool through the rad. you have other issues. removing the stat should make overheating worse.

 

[5spd GT]

Troy - It will at low speeds but the radiator takes care of that at highway speeds.

My car is now doing the exact same thing it was earlier (with the t-stat).

I hope all my freeze plugs are good.

I am going to be replacing the headgaskets and intake gaskets here in just over 2 weeks when I do some work on my car. Ported lower, longtubes and some other trinkets.

I heard the hissing noise the first time it ever overheated but it ran fine for well over a month before another problem arised

It is kind of hard to till if smoke is coming out of exhaust that shouldn't be. It is a bit chilly here...

Thanks for all the replies guys!
My car has always cooled awesome on the highway till recently. I'm not sure why the radiator would go south all of a sudden and it is a nice one IMO.

 

[Michael Yount]

If it's detonating when 'hot' -- that adds up. The engine's inability to reject heat is raising temps in the chamber which will eventually lead to detonation. So that's good from this perspective -- we know it's actually getting hot. As you might imagine -- the stock gauge/sender RARELY gives a warning before it starts doing funky things.

My experience about removing t'stat's has been exactly the opposite of troy's -- this time of year (cool) removing the t'stat (or a t'stat that's stuck open) results in the car running exceptionally cool. So cool that many automatics won't even shift into overdrive -- because the computer thinks the car is still cold; because it actually is cold.

How old is the radiator David? When was the last time the system was flushed and the coolant was replaced? What kind of shape/color was the drained coolant in? Can't remember from the other thread -- does your lower hose have a spring in it? (squeeze it -- you'll feel it or not)

Pull the dipstick and see if the oil looks clean --- the old 'milkshake' look is what you hope you don't see. Who knows -- perhaps the original overheat did more damage than we thought.

 

[Michael Yount]

We posted at the same time David -- if you're about ready to tear it down, you'll get to the bottom of it. But with the temps and detonation - I'd sure try not to drive it if I could avoid it.

 

[Michael Yount]

By the way -- the best way to check for exhaust smoke is to have someone else follow you -- after the car is completely warm. If it keeps blowing lots of condensation - that's a pretty good clue that coolant's getting in a chamber somewhere. And blue smoke is pretty easy to see as well -- just do a 2nd gear 2000-5000 hard run, and then back off with it still in gear. If it's smoking blue, your 'follower' will see it. It's actually pretty hard to see from inside the car unless it's really smoking a lot.

 

[HISSIN50]

The whole thing with coolant flowing too quickly might have been true back in the day (low pressure systems) but it is not so true now. The longer coolant is in the motor, the more opportunity it has to boil off (hot spotting). One wants to force it through the system at decent velocity.

 

[Rynb15]

i had a blown headgasket in my lt1 camaro. It overheated once and then it was fine for a few weeks. And then it would overheat maybe once a week. Couldnt figure out what was wrong. Then it would get up in the temps after about 5 min and it looked like a steamboatwas driving down the street. crapola

 

[JB66]

Are you getting any foaming in the coolant in the radiator? I don't remember anyone asking that. The only thing in the engine that's able to overheat the coolant is the exhaust. An exhaust leak into the cooling system won't show up anywhere externally except in the radiator. Possible cracked head.

 

[5spd GT]

The car actually drives fine overall

I don't notice anything just out of the ordinary except for excessive heat. I don't notice the detonation like I did the first one or two times it showed "hot" on the guage.

I agree, the teardown will show what is up I hope...

I just figured the no t-stat would have enough coolant flowing in and out to keep it down in temp for a week or two but it is doing the exact same thing that it did with the t-stat according to the guage

I don't have a spring in my hose, I am almost certain...

 

[5spd GT]

Just looking for more opinions

I think I am loosing coolant because it does seem just a bit lower than usual but I always wondered if that was because I was spewing coolant out of my overflow tube and losing it.

Radiator is a bit over a year old. Very doubtful that that is the problem.

My clutch slips to bad to even due a "smoke test"...but it might be smoking just a bit more than usual.

Now why would my car run "hot" most of the time and then for no reason the car will get cool on the temp guage (heater will then start working) and then the temp will climb up pretty quickly again...

Almost like an airbubble again or something? But there is no t-stat.

 

[TheUser]

have you tried having your heater always on? This will allow some of the heat to escape via the heater. You could turn it on the floor position if you don't want it blowing on you. Just an idea for a band-aid.

I'm no engineer like some of these guys, but I don't think you have to have a thermostat in to get an air bubble. An air bubble would just be because you allowed air in the system and it didn't get out since it's a closed and pressurized system.