72zcar Posted April 1, 2003 Share Posted April 1, 2003 could be a faulty thermostat. I bought a new thermostat from msa and was faulty right out of the box. I would get on the highway and temp would go up. Swapped it out and no more problems. Quote Link to comment Share on other sites More sharing options...
pparaska Posted April 1, 2003 Share Posted April 1, 2003 zya - the bottom hose being cooler with the fan running all the time versus being warmer with it only running with the thermostat means to me that the fan running all the time is over cooling. I doubt that the fan running will block the air while moving. On the contrary, the stationary blades would be blocking. The fan is helping pull air through at a high rate. Someone mentioned that maybe the seal between the radiator support and the radiator wasn't good. I used that same radiator and the GT Mustang fan (same motor) but made sure I sealed the radiator to the support opening well. All air going through the radiator hole in the support has to go through my AC condensor and radiator core. I'd make sure that is all sealed up. Also, there are large holes on either side of the radiator that you could plug up as well. Are you sure you have a water pump that pumps in the correct direction? The LT1 has a reverse flow pump. Quote Link to comment Share on other sites More sharing options...
z ya Posted April 1, 2003 Author Share Posted April 1, 2003 Yeah, I just have the standard autozone long style pump. I will keep you guys posted . Quote Link to comment Share on other sites More sharing options...
Mudge Posted April 1, 2003 Share Posted April 1, 2003 LT1s have a special thermostat and the reversed circulation, I didn't know it was an LT1 car, or is it not? From your sig I'm not guessing it is. Basically if you bought a $5 thermostat its SBC not LT1, if you payed $15-$20 its the right one. Quote Link to comment Share on other sites More sharing options...
Guest greimann Posted April 1, 2003 Share Posted April 1, 2003 Mr. Z ya, How hot is hot? What temperature exactly are you seeing that causes you concern? Quote Link to comment Share on other sites More sharing options...
z ya Posted April 1, 2003 Author Share Posted April 1, 2003 The car used to run between 190 and 200 . When I wired the fan to the key it ran the same in town but would climb to near 230 on the highway. If it run s between 190 and 200 I will live with it. I just feel so much better with it at 180! Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted April 2, 2003 Share Posted April 2, 2003 You might try a chin pan. Helps reduce turbulence underneath the car and smooths out air flow through the radiator at speed. MSA sells the Nissan part. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 2, 2003 Share Posted April 2, 2003 What type of gauge are you using and are you sure it is accurate? Quote Link to comment Share on other sites More sharing options...
Mudge Posted April 2, 2003 Share Posted April 2, 2003 It shouldn't run at 180º unless you get a 160º thermo or thereabouts. They begin to open at thier rated temp, they dont fully open for awhile, and 180º or higher coolant temp would be better for all around gas mileage etc anywho. Quote Link to comment Share on other sites More sharing options...
z ya Posted April 2, 2003 Author Share Posted April 2, 2003 Autometer guage Quote Link to comment Share on other sites More sharing options...
Racin_Jason Posted April 2, 2003 Share Posted April 2, 2003 Here's my opinion Zya... Testing is your friend. Although it may be tedious, its the easiest way to find a problem..by eliminating possible offenders. I'd stovetop test your thermostat. Power flush the system and look for low flow starting with bottom hose off WP. Swap the rad...%&*%..i know. I think you might have a partially clogged radiator that only restricts badly at sustained mid-high RPMS. More pressure from the pump on the freeway and its much more steady pressure. Some boogered up passage ways in the rad could back that steady flow of water up...but the variance of RPMs around town would allow it to pass at low RPMS. Something to ponder Jason Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 2, 2003 Share Posted April 2, 2003 All you guys are cracking me up!.....LOL. Obiously the temp gage is wired backwards.....NOT! Anyway, 190 should be ok to ease the cap off, then rev the engine and see the pretty water ripple by. I f not then you got thermostat problems. But if you have a 180 and get 190 reading thats not so bad. You can check the therm. by putting it in a pan of water along with a Deg. F thermometer of some sort. Watch the them both as the temp reaches the stamping on the therm. If the thermostat dosen't begin opening at that point then observe when it does and mark this as it's true value. New stuff can be defective you know. It sure sounds like there is no circulation but I would think it would get hotter than 190 on the highway without circulation, boiling is more like it! The thermostat may not be opening fully so if you pan test it make sure it opens all the way before the water boils (212 deg). PS: And don't tell me you got the thermo on backwards for gosh sakes! The bellows goes to the pump side.....LOL Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 4, 2003 Share Posted April 4, 2003 well, lets over examine this.....the car should run at its hottest in traffic due to slow air speed through the radiator and slow water speed through the engine. If it runs at a good temp in traffic then it would seem that air flow and water flow are GOOD. Highway driving provides increased air speed through the rad and sustained water speed through the rad, so if you are heating up there I think the problem is elsewhere. Two possibilities have already been pointed out; faulty thermostat (they can close all on their own sometimes! weird) and too much water flow through engine (usually when no thermostat is present, and the water does not have enough time to pick up heat from the metal). Check this out: Sometimes head gasket leaks can occur very slightly and hard to diagnose. The leak will sometimes only be pressure passing from the cylinder to the water jacket (pressurizing thus overheating the coolant, particularily under high load or sustainded engine speeds). This can be hard to find, as in one case I experienced NO water was passing into the cylinder so no oil-water contamination to give the leak away. Look for tiny bubbles running through the coolant while engine is running at moderate speed through the rad cap opening. Hope it is something much simpler than this that is causing your problem! Head gaskets can be a bummer to fix.... Quote Link to comment Share on other sites More sharing options...
Mike C Posted April 4, 2003 Share Posted April 4, 2003 Also noted earlier is the lower hose could be collapsing if the spring is not present and I don't know if it has been mentioned, but a rusty or damaged impeller can flow water at idle but have sufficient cavitation at speed so as to not pump any water. Quote Link to comment Share on other sites More sharing options...
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