JimmyZ78

Well, first off its a stock bottom end APS tt car. 317's, etc....

I picked up the car from the shop and it ran about 240* the whole way home. So I started looking into it and saw a stocker t'stat of 195 in there. To temporarily fix this problem I decided to cut the t'stat guts out so it would just act as a restrictor a little bit. I ordered a 160 stat btw. After driving that, and realizing that wouldn't fix it I ordered a Dewitt's w/o eoc. Installed it this morning, three bottles of WW and plain water for the rest. I drove it around for awhile, prob an hour or so and I see max of 235* Still to hot in my eyes. I come home, let it sit for awhile. A couple hours later I take it back out for another drive and head to the ball park. Hour and a half later I get back into the car, temps are 215*. Start to head home, get to a light, sit there for a minute, start driving and temps steadily climb up to 255* So I pull over and let it sit. Temps go up to 280* I tried to just let it idle to keep the fans on and that didn't help. Temps were coming down slowly with the car off.

Car has been tuned. Fans come on at 175* and full power by 185* When I changed the radiator I blew out the condensor because the radiator was clogged. Upon putting it back together I made sure the shrouding was fitting correctly.

I don't think it could be an air bubble because there is no t'stat in it. Fans are working. I'm using Water Wetter. New water pump.

WTF, any ideas.

brookman

Have you checked your temps with an infrared gun. Maybe your temp sender is wrong.

Did this just have head work done? did the gaskets get put on the right direction?

Bill Curlee

Is there trash in the shroud and is there trash in between the AC condensor and the radiator. Another thing to check is to see if the internials of the radiator are clogged. If the cooling system wasnt properly cared for by the other person, the dexcool could have clogged the internal cooling passages inside the radiator. A good radiator shop can see if the radiator is flowing the correct GPM.

Next on the list would be to see if the pump is flowing the correct GPM.

BC

JimmyZ78

Well its a brand new Dewitts, brand new water pump and I did blowout the debree in the condenser. The heads were installed and I would be willing to bet that the gaskets were installed correctly. I am sure it would overheat alot faster than it has if they were on backwards.

Bill Curlee

Could the sensor be bad??

Reading HIGH when the engine is really normal???

BC

gpracer1

Did you say there is NO thermostat in the car?

JimmyZ78

Well, there is, but no guts. I basically made it a restrictor. Its 105* out right now. I was thinking this might be a problem since the coolant can't stay in the block long enough to transfer heat but wasn't 100% sure of that. Thats why I was thinking leaving the disc in there just to help. I had a 160 to put in it, but its the wrong style so I just went with the modified one I had in there.

The sensor is good. New sensor. Its damn hot under there.

BATM4N

It's gotta be b/ of no t'stat. Thats too much of a coincidence. It can't be a bad a bad sensor if its as hot as your saying it is under there. my .02

Bill Dearborn

Without the thermostat the coolant is passing through the radiator too fast to cool. If GM could have gotten away without a thermostat they would not have put one in. Parts that are not necessary cost money and fail so automakers do not put them in if they are not necessary.

Bill

coupeguy2001

I live in phoenix, and at 110* my 01 coupe runs 200-205 on the highway, 214 when I get off the fwy, and 212-214 traffic. Your problem has to be a plastic bag or somethin sucked up in there. I had a 1/2 styrofoam cup up in there once dancin around.

JimmyZ78

So I had to park it on the way home last night as I didn't get two miles again and it was up to 250* I went this morning and put two gallons of distilled in it and it ran 180* for the short trip home, getting on it twice. Mainly just first or second, short bursts. Anyway, I park it and it pukes water out. So either I over filled it just to make sure or I got some major problems now, probably from the major overheat. I'll order the t'stat tomorrow and try that but i am doubtful at this point.

tabbruzz

Is the coolent level ok or do you need to keep adding it? You replaced a lot things for this to keep happening. If you are sure that the fans are coming on perhaps you have a blown headgasket....Just a thought....

BlackZ06

2 GALLONS ???!!!!

The stock system only holds a little over 3 gallons ..... sounds like you never got the air out of the system and have been running seriously low on coolant. Did you remove the overflow reservoir ??? The stock set-up is designed so that the reservoir is pressurized ... the cap on the radiator is NOT a pressure cap ... the cap on the reservoir is the pressure cap. It is designed this way so that any air in the system can pretty easily bleed into the reservoir and be replaced by coolant in the reservoir.

Also, the engine SHOULD have gone into "Overheated engine protection mode" at about 265 degrees. Did it do that???? You should be able to drive the car with NO coolant in it once the PCM switches to that mode.

crvtble

You said you picked the car up at the shop. What did you have done ?? The APS install...?? If so, you should go back to the shop, maybe something wasn't installed right. If you are seeing 250+ temps...a different thermostat won't be the fix..sorry

HIGHRPM

Not true.... the t-stat is only needed for a quick warmup in cold temps...it restricts water flow until near operating temps are achieved. Then its wide open and allows full flow. With the fans on the coolant cannot pass through the radiator too fast to cool it...I had a long talk with engineer Steve Prestley of Evans about this subject....he said that I should weld a plate over the bypass on the Evans high flow pump to INCREASE flow and not use a t-stat. This has corrected all my previous overheating problems....even on 100+* days my temps are always under 200.

I think your problem is either air in the system or a blockage somewhere in the motor..... your not getting enough flow through the radiator.

madmatt9471

Sounds crazy but check to see that the fans are turning in the right direction!

Yes someone could have crossed the wires if work was done on the Vette!

Plus it is possible for the fans to not be turning at the proper speed for cooling or at least one of them and in this case it could be your HIGH SPEED fan your secondary fan!

Check these and let us know what you find! I've seen it before!

Thanks,Matt

BlackZ06

HighRPM,

From the Service Manual ..... ENGINE COOLING - Description and Operation ...... (page 6-508 in mine)

The thermostat also provides a restriction in the cooling system, even after it has opened. This restriction crreates a pressure difference which prevents cavitation at the water pump and forces coolant to circulate through the engine block.

I still go back to my post above ... between no thermostat, and adding 2 GALLONS of water ... that's a cooling system begging to not work.

JimmyZ78

The shop did do a APS install and I WON'T Take it back to him for any reason. I am to the point where I don't want the car anymore as I am that disappointed in it. The fans are turning, they are pulling. They sound like they are on high when the temps are above 200 which is what they are set for, well 185*. There is a restrictor in the t'stat location right now and its possible that I didn't get the air out. I could have over filled it as well. I was more interested in getting water in it and getting it home from the parking lot it was in overnight. I'm not sure what the deal is yet but I will keep plugging away at it. It just sucks that I don't have a gargage to do this all in and I can't do this stuff at work. I'm a mechanic and I can't work on my own car at work. I will put a 160 in it and get it to op temp and just put a hose in the res and turn it on to help force any air out. I wouldn't think there would be air in there with no t'stat, but I'll give that a shot.

BlackZ06

You're not responding to my posts ... look at the one directly above yours ... YOU NEED A THERMOSTAT IN THERE ... that is CLEARLY stated in the Service Manual for the car.

Also, furhter above I asked you if the car went into "Engine Over-temp Protection mode" ??? Did it ????

If not, your PCM programming has been seriously screwed with.

JimmyZ78

Sorry I missed that. I thought I responded when I said I will be putting in a 160 stat as soon as it arrives and I will retry it. I can tell you that the tune is good and not messed with. I will let you know updates after I get the 160 in and get it purged correctly.