angelck022

I did quite a lot of modding to my rex a little over a year ago. Went single, upgraded the fuel and cooling components to support the mods, but it seems to me the car is running hotter than it should be. I have no evidence the car is actually running hot-- but the gauges are indicating rapid temp changes. I am very cautious and never let the temps get over 90 degrees C on the pfc-- but I think it would get over that if I let it. Also, the idle temp is stays between 75-78 degrees C.

I am running the undertray, aftermarket ast, koyo radiator-- brand new, new overflow tank, and most of all I am not losing any coolant whatsoever. Even the coolant filler neck cap is new oem. I have done all of the recommended tests and everything checks out fine.

My thoughts are that the coolant temperature monitoring devices could be worn out and need replacing --resulting in unreliable temp readings. I have orderd a new thermostat, coolant level sensors, etc. but just wanted to get some of your feelings/thoughts/ideas as maybe I have overlooked something simple.

One last thing that might be a related, the heater has not worked since the day I got the car-- only blows cold. I know the heater cores are prone to failure, but I am not sure if this would cause the rapid changes in temp that I am experiencing.

adam c

iTrader: (2)

The first thing to do is check that your fans are coming on when they are supposed to, and that all of them are working. Improper fan function will result in overheating.

angelck022

I will double check that-- I am pretty sure the fans were set by groundzero when they tuned my car. good Idea, thank you.

Nuvolari

iTrader: (4)

Whats in your Rad ? as in water-coolant , what % ?

What type of IC do you have ? Stock mount, FMIC , V mount ?
Also has the thermostat been replaced ?

DrunkenBowler

I would check the fans and maybe to the fan mod if you haven't done so. I see you are changing the thermostat. That's a good thing as well. My heater core always blew cold air for the longest time. So, I changed the thermostat and it started working. Now, it just get's hot as ***** inside the car because I have taken out the transmission tunnel insulation. I'm going to wrap my dp, mp, and exhaust here shortly.

angelck022

the coolant in the rad is approx 50/50. My intercooler is a greddy front mount, and no the thermostat has not been replaced since I have owned the car-- bought it 6/2004.

Hopefully the thermostat change will get my heater working also! that would be nice.

moconnor

iTrader: (14)

What do you mean by 'let it'? You turn the car off when the temperature reaches 90C? If you are that paranoid, I would buy a Datalogit and set the fans to come on at 85C. On my car at least, they do a very good job of controlling temperature. even with lots of boosting.

angelck022

I am headed into pineapple racing on wednesday-- so I will have rob take a look at it. I am sure I am just being overly cautious, but when I first got the car the temp was very consistent on both of my temp gauges no matter how hard I drove the car I would rarely see 90 degrees C. Now if I have some spirited driving, or get under boost a little bit (5psi) it is nothing to see the temp jump from 78 - 90 in a few seconds. this is mainly the concern that I am having.

angelck022

I don't drive the car much so it hasn't really been a huge issue until now. I want to get this worked out before my car gets put on the dyno in a month. gotta keep the thing cool while going for 350-400hp.

Sgtblue

iTrader: (16)

Seems like what your saying is that you see more dramatic SWINGS in temp then you saw before mods...but it's not overheating.
If so, maybe that's not all that abnormal. More power, more heat. As long as the system is recovering within safe ranges, maybe it's nothing to worry about.

angelck022

yeah, you are probably right. I am going to replace the temp sensor, thermostat, and coolant level sensors (as I am not sure how old they are)--- if nothing else it will give me peace of mind.

Sgtblue

iTrader: (16)

Filling the gaps around the radiator with some upholstery foam is also pretty effective....and cheap.

Sprockett

Fan Mod FTW

trainwreck517

iTrader: (1)

Fan mod is usless if he has a PFC to lower the temp in which the fans come on.

90*C is nothing to worry about.. start worrying around 100*C.

90*C is only above operating temp by 5 degrees.

If the temp increase is rapid form 84->90 degrees.. like under a min or two.. sounds like maybe your thermostat is having a slow opening time. So changing that should help.

Also with your FMIC.. your temps will be a little bit hotter.. but should still be under control. Beat on it for a while and see if they exceed 100*C.. if your really paranoid.. then let off if you see 98*C.

Hope that helps.

Sprockett

I missed the part about the PFC, sorry

Veger

Imo the easyest and cheapest way of controling the fans is with the peti or HKS fan controler, its only 3 wires from the ECU and you can tell the controler what temps you want the fans to kick in at, i used to get 90c in trafic constantly and sometimes 95 if there was no air flow through the rad ie uphill in rush hour trafic, i installed the peti fan controler and set it to 85c and its never gone beyond that for 3 months, took me 1hr to fit it (thanx 2 Dale for his support).

There is a installation rightup on Dale Clarks website if i remember, Fan controler is a fantastic pice of kit and i dont understand why people dont use them more.

Veger

Sorry my mistake, mine is a pivot not peti.

This is what i have http://www.pivotusa.com/installationman/pivfcg.pdf

Amazing pice of kit if i do say so again.

moconnor

iTrader: (14)

He has a PFC so all he needs is access to a Datalogit for five minutes to set the fan speeds.

Veger

Well duno how easy it is for him to get hold of a datalogit but its near impossible for me or i would have dun the same with my pfc.

Got to point out all the options.

Or am i wrong ?

Str8Down

Are we seriously trying to address 90C temps????? Dude 90C is PERFECTLY normal. Leave it alone. 100C is just fine as well,. A for 78C normal temps, do you nothave a thermostat? It doesn't even open till 82C, so how is your car holding 78C? And if it is, that is bad, as your car is not reaching operating temps.