260zjade Posted October 13, 2006 Share Posted October 13, 2006 I know a guy that works at the local autozone and when i went in today to ask for a thermostat for my 260z, he told me that to fix my overheating problem, i needed to cut the thermostat and take out a washer and some other junk, ultimately causing the thermostat to stay open, but slightly restrict the flow of coolant, creating a slowly flowing, opened valve. Does this make sense? and if so, why wouldnt just taking the thermostat out work instead of this mod? He also said backpressure can significantly increase heat output or something. My muffler is seriously dented near the rear of the car, and i think it could cause a pretty good amount of backpressure, but could this be why my car is overheating, or even a contributor? thanks in advance Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted October 13, 2006 Share Posted October 13, 2006 circle track racers use a restrictor washer, several sizes available. Muffler, definately. Quote Link to comment Share on other sites More sharing options...
Kennysgreen280zt Posted October 13, 2006 Share Posted October 13, 2006 The Z car mech here swears that you need to use a OEM thermostat.... I personally dont believe it, I havent had any issues with FLAPS thermostats. Another thing to check, well with what I know of your car, make sure there is nothing restricting airflow to your radiator. Also check to make sure your fan clutch is in working order. Quote Link to comment Share on other sites More sharing options...
260zjade Posted October 14, 2006 Author Share Posted October 14, 2006 there is nothing restricing flow to my radiator but the ac condenser...i think thats what it is....and its in relatively good condition...and i dont have a clutch fan...i took it off to stop it from whacking my old radiator...i went through 1 radiator and two fans because my fans were hitting the top lip of the radiator...so i have an electric fan that i need to upgrade and a brand new radiator...it does fine at cruising speed, but when im doing start and stop or idling, it gets pretty hott...i need to change the thermostat cause it may be bad, but i was curious if my autozone guys idea was credible... Quote Link to comment Share on other sites More sharing options...
A. G. Olphart Posted October 14, 2006 Share Posted October 14, 2006 there is nothing restricing flow to my radiator but the ac condenser...i think thats what it is....and its in relatively good condition...and i dont have a clutch fan...i took it off to stop it from whacking my old radiator...i went through 1 radiator and two fans because my fans were hitting the top lip of the radiator...so i have an electric fan that i need to upgrade and a brand new radiator...it does fine at cruising speed, but when im doing start and stop or idling, it gets pretty hott...i need to change the thermostat cause it may be bad, but i was curious if my autozone guys idea was credible... Your autozone guys theory might have some relevance in circle track racing, where engine output is near max all the time (fairly stable heat load), but sounds like BS for a street car. Engines like to be at 180 up for maximum life, and thermostats can bring you there quick, then hold a temp. Not all thermostats are created equal; the pressure balanced type works more consistently, especially with a high flow water pump (which can make it hard for some cheaper t-stats to open). Good cooling at speed, poor cooling in town/stop and go is an indication of insufficient air flow at low speed. Perhaps a better electric fan, and/or modifications to allow air out of the engine compartment when putzing around. <> Quote Link to comment Share on other sites More sharing options...
roger.svoboda Posted October 14, 2006 Share Posted October 14, 2006 Agree with olphart (being one myself). That is what a thermostat should do and if you just take it out your engine temp varies all over the place. Why would a guy working for $6 an hour at autozone be an authority? If the muffler is dented enough to seriously raise the back pressure the car would run like &^%$%^. Two things would cause high temp. Insufficient flow of coolant (bad pump, kinked hoses, restriction somewhere in the coolant Path). Insufficient air flow through the radiator (electric fan not running or not large enought to supplly sufficient air.) Assuming the radiator you put in is of the correct size for the vehicle. Quote Link to comment Share on other sites More sharing options...
260zjade Posted October 14, 2006 Author Share Posted October 14, 2006 im pretty sure the rad is good...and i probably need a new fan...but i never thought about my pump...see the problem is...i dont know anything about this car aside from what ive discovered...the guyi bought it from didnt tell me anything... Also, the other day i flew down the freeway to get my temp up, and then i got off and let my z idle till it got nice and hot. Then i popped the hood because i heard thats a good way to see if theres too much heat in the engine bay that cant escape, and there was no change in the temp...i think it was still going up...so i dont think putting a fan system or something in there would help much...but i could be wrong...im new at all of this... I suspect that getting a cross flow radiator with multi-cores would eradicate the heating problem, but of course i think of this after buying a new radiator. the flow goes straight down on mine, and i wonder if the coolant is getting enough time too cool off. Anyway... so my rad is new and functional, my hoses appear to be good, and i have a fan, but not the best...which means i need to check my pump, change the thermostat, and possibly get a bigger fan...its winter now, so she doesnt get so hot anymore, but i will tie up these loose ends, and then get back to you guys...thanks as usual for all of the suggestions...and sorry about the unusually long posts... Quote Link to comment Share on other sites More sharing options...
mom'sZ Posted October 14, 2006 Share Posted October 14, 2006 The reason for placing some restriction in the system instead of simply eliminating the thermostat entirely is to slow the flow of coolant through the radiator. The coolant will actually pass through the radiator to fast to get cooled off. So the guy at autozone, his idea has a certain amount of validity, but I believe as do many others, that a street driven vehicle is much better off with a thermostat. It helps to quicken warm up and maintains a stable temp. Sounds like you need a bigger electric fan or a mechanical one that doesn't hit anything. oh, and fix that muffler. Quote Link to comment Share on other sites More sharing options...
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