C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Engine Temp Creeping Up

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Old Dec 10, 2004 | 11:44 PM
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Default Engine Temp Creeping Up

I'm used to my vette running nice and cool, around 185 when cruising around the city, and 170-175 on the fwy, sometimes cooler depending on the outside temp. I've noticed the temperature slowly getting higher and higher day after day, until now, it heats up to about 210 when cruising on the street. Also, my engine oil temp will shoot up around 215, taking the coolant temp right with it. I have a 160 thermostat, a new high flow water pump, and a high flow high volume oil pump. I'm a bit paranoid about engine temp since I overheated my first car, and I've done everything I can to keep my car running cool for performance, and for my state of mind. BTW, I have changed my cylinder heads to 91 with the 58cc chambers, which increased my compression to 11:1, but the temperature has been fine up until the past couple months. The top end of the engine was rebuilt summer 2003. Could it be a faulty thermostat? I dunno, whats an awesome, reliable brand to buy of thermostats so I'm not changing them ever year?
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Old Dec 11, 2004 | 12:08 AM
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From: Kailua Kona HI
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bypass your electric fan and leave it on for awhile and see if this helps.

New water pumps go bad. This would be my first guess. Make sure it's the proper pump and your belt is driving it properly and tension is good.

I don't know how to check a radiator's flow. Your car is like mine and old.

Changing a thermostat is easy. You can also take it out completely for a test but I'd just change it.
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Old Dec 11, 2004 | 12:47 AM
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From: eville in
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Cats. clogging up act's like that sometime's
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Old Dec 11, 2004 | 12:48 AM
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Could be any number of things. The thermostat could be not opening all the way. There could be some other obstruction to coolant flow. A failing water pump is possible but this seems like it would manifest itself in other ways (slipping belt, leaking, etc) Take the belt off and try to spin the water pump by hand, you should be able to fairly easily.

Another common problem with the C4 is trash getting sucked up into the radiator. Your entire cooling system can work perfectly but if there's not enough airflow through the radiator it'll overheat.
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Old Dec 11, 2004 | 12:59 AM
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How many miles on the bottom end? Before you go crazy it could be debris between the radiator and AC condensor. Check that first, when I did mine I was amazed at what I found.
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Old Dec 11, 2004 | 01:03 AM
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My money is with Nathan. You have debris (leaves this time of the year) that has been sucked up and are clogging your radiator. First look into the opening at the a/c condenser and straighten fins and remove any debris you find (leaves, sticks, cigarette butts, plastic bags, etc). A low effort way to clean your radiator from debris is to take a garden hose and adjust for a high speed small stream and blast water backwards through the radiator and then blast water around the radiator cap gap to flush the debris out. Otherwise you have to take the top cover off the radiator to get to the front and clean the debris out. The garden hose method is easy and will tell your right away if it was debris by driving your car afterward and observing the operating temperature.
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Old Dec 11, 2004 | 01:24 AM
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So, the debris can hide in other places besides the opening under the bumper?!!!! Argh!! Ok, I'll check it out, since its been so gradual, it just might be that. Is it rough to pull the cover? Sadly, I had the radiator changed when I was still in school, and had someone besides myself do it. Thanks guys!
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Old Dec 11, 2004 | 01:48 AM
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I'll have to check mine when I get it back from the shop. Mine used to be fine around town, yet any speed above 45 it would start heating up.Good info here
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Old Dec 12, 2004 | 08:08 PM
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I checked out my catalytic converter. The air hose is broken...so, maybe the cat is slowly clogging. I'll patch the broken line. If I get on it after driving around a bit with the repaired air hose line, could that help to clear the cat out if it were clogged? I didn't see much debris near my radiator, just a few leaves, like 3, and all the fluids are good. Thanks for the tips everyone!
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Old Dec 13, 2004 | 05:01 PM
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Yeah...scratch that last post. I checked the cat, looked might like the one I gutted...checked the cat I had in the box, its my original. Guess my mechanic was listening when I asked him to swap it back. Funny thing is, it is as LOUD as with my originanl cat (my car is louder inside with a catalytic converter, don't ask, cuz it doesn't make sense to me). So, the cat filling up, is now off the list of things to cause my engine to heat up. I dunno...surprised me though!
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Old Dec 13, 2004 | 06:51 PM
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Originally Posted by 84Coyote
Yeah...scratch that last post. I checked the cat, looked might like the one I gutted...checked the cat I had in the box, its my original. Guess my mechanic was listening when I asked him to swap it back. Funny thing is, it is as LOUD as with my originanl cat (my car is louder inside with a catalytic converter, don't ask, cuz it doesn't make sense to me). So, the cat filling up, is now off the list of things to cause my engine to heat up. I dunno...surprised me though!
Debris in the radiator probably won't be obvious till you take off the top cowling and look between the radiator and the AC condensor. Sometimes you can see a leave or two peeking out, but you need to pull the cowl

I have had thermostats go bad in the past, but here my symptoms have been rapid warm up at the the traffic light and slower than usual cool down once I start rolling again

seeya
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Old Dec 13, 2004 | 07:01 PM
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Eliminate all your worries, here is the answer to all concerns !

Increase CFM
Decrease debris and water contamination

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Old Dec 14, 2004 | 11:22 AM
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Default Tstat is a cheap part...

I would probably start there. I'm sure you looked for ap-cray between the radiator and the A/C condensor.
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Old Dec 17, 2004 | 02:18 PM
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Another quick thought, check your radiator hoses. If they are old once preasure from the radiator builds, the thermostat opens, it could collapse or seemingly pinch off your water flow. while cool pinch the hose in the middle but not near the inner spring. It should not be that easy to pinch it together.
Woody
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