started running hot
started running hot Hey guys. Was driving down the road tonight at about 60 mph in 6th when the temp on the car started suddenly increasing. I had been driving for probably 20 minutes or so. If I push in the clutch and rev it the temp would come back down. Then as soon as I let the clutch back out and the RPM dropped it would shoot right back up to just before the red or into the red. I replaced the water pump, hoses, correct thermostat, etc. about 5000 miles ago. Also I have a tune by Madtuner which is supposed to kick the fans on sooner (shouldn't matter going down the road at 60 anyway). When I got home I plugged in the scanner to see what temp it was showing and it read 230*. After it cooled down I checked the antifreeze and it's full. No leaks anywhere. If the gauge was just reading improperly would the PCM read the same?
Your PCM uses a second sensor to read the temp, not the same one the gauge uses. To be over heating driving 60 is hard to do 
check your rad for trash and other junk that may be blocking air flow. You may have just replaced the water pump but they can still fail and start leaking from the weep hole almost right away if it's bad, double check. Sounds like you have a coolant flow problem though, sticky tstat, pump failing.
check your rad for trash and other junk that may be blocking air flow. You may have just replaced the water pump but they can still fail and start leaking from the weep hole almost right away if it's bad, double check. Sounds like you have a coolant flow problem though, sticky tstat, pump failing. 
TECH Resident
Joined: Apr 2010
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From: T E X A S
probably an air pocket. refill procedures are found on www.shbox.com
follow them verbatim. and allow a few heat cycles (without overheating) before trying to diagnose other problems such as a leak (waterpump bolts especially in your case)
follow them verbatim. and allow a few heat cycles (without overheating) before trying to diagnose other problems such as a leak (waterpump bolts especially in your case)
I checked last night to see if I could see anything blocking the radiator and couldn't see anything. I'll get a better look tomorrow. The stat going bad and possibility of an airpocket were the first 2 things I thought of as well- but I followed the directions on shbox's site the first time and haven't had a problem up until last night. What threw me off is why the temp would come back down when I revved the engine- then shoot right back up when running low RPM again.
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At 18psig water boils at 256 degrees so I'm not entirely convinced this is a possibility. Even then for flash gas to form in the water pump that quickly AND for the sensor to react that quickly just seems unlikely given the amount of heat coolant/water must absorb to transition from liquid to gas (latent heat = 970.3btu/lb.).
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Verdad Gallardo TECH Resident
Joined: Apr 2010
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From: T E X A S
Idk, I have had a lingering air pocket problem myself. hard cornering or braking would drop the temps (on dash) QUICKLY, but when using the laser temp gun everything was ~ 180 even though the dash would say it was at 220+
I put in a new stat today and topped off the antifreeze. Figured I'd start with the cheap (free since the Stant has a lifetime warranty 
) stuff first. Bled with the bleeder valves and drove around for 1/2 hour. No problems yet. RamAir the coupling and gear looked good last time I had them off a few months ago. I've got a spare coupling just in case. I really hope that isn't the case because I would hate to have to pull the timing cover off again! I was thinking about it and a few miles before the temp gauge started going up I passed a semi- maybe revving it out in 3rd was just enough to get rid of an air pocket? Weird that I haven't had a problem before now though- I usually drive it pretty easy but that's definately not the first time I've gotten on it since I drive it every day...
) stuff first. Bled with the bleeder valves and drove around for 1/2 hour. No problems yet. RamAir the coupling and gear looked good last time I had them off a few months ago. I've got a spare coupling just in case. I really hope that isn't the case because I would hate to have to pull the timing cover off again! I was thinking about it and a few miles before the temp gauge started going up I passed a semi- maybe revving it out in 3rd was just enough to get rid of an air pocket? Weird that I haven't had a problem before now though- I usually drive it pretty easy but that's definately not the first time I've gotten on it since I drive it every day... 