Engine heating up with dual fans and XFI help?

Hello all, so temps have picked up in my area and I started driving my car around. Yesterday it was in the high 90's and was driving highway speeds of 70 to 80mph and car stood at 200 and would creep up to 220. To hot for my blood. So I would pull over and let her cool down. I had dual electric fans running the whole time. They are triggered to come on with the XFI at 175. But with them both on that wasn't enough to brings the water temp down while driving. What do you guys think it can be or where should I start?

grass doctor

Dream Catcher
160 stat ?? pull the thermostat and drive it see if it runs cooler, what type of hoses, if your lower hose is collapsing this will cause overheating, there was a spring in the OEM rubber lower hose for this , is radiator full , radiator clogged possible, are you using RMI additive in it ? water pump worn out
Front mount Intercooler?
Yes have a front mount intercooler.

The hoses seem to be good. I can't visually see nothing collapsed and I do run antifreeze. I am not sure what thermostat is in the car so I guess I can start with removing it and see what happens. It was just hard for me to believe with 2 electric fans running full speed it would not bring down the temp on the car.

grass doctor

Dream Catcher
most se overheating at idle while not moving , cooling systems is pretty simple with only few components , so drive without the stat in and if no charge this will lead you to a improperly functioning/clogged radiator or worn out impellers on water pump, you will only be able to see if hose collapses if looking while reving it up, RMI is a cooling additive that cleans and lubricates the system, might be time for a clean and flush,
the spring in lower hose can rust away and an old hose will collapse, they have new silicone hoses will will last long time and do not require a spring , I think even the newer rubber hoses don't require a spring but I don't trust that


Well-Known Member
My guess would be no air deflectors to box in the FMIC/Radiator and direct the air through the cores.... you can add a manual switch to turn on the fans at highway speeds or fab up some air deflectors/box in kit to direct air flow

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My guess would be no air deflectors to box in the FMIC/Radiator and direct the air through the cores.... you can add a manual switch to turn on the fans at highway speeds or fab up some air deflectors/box in kit to direct air flow

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I never paid attention to see if i have the air deflector. I'm going to check that and try removing thermostat. Let's see if that helps. How would I know if my front mount is dirty or clean? Visibly looks clean?


Well-Known Member
Also what radiator are you using? And previously did it drive cooler in hot temperatures? Or is this your first time driving in these temps?

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It dont get driven much and from what I recall when I did drive in these temps it would touch 200 then temp would drop down to 170 then back to 200 but never get hotter then that. The other day in the heat It stood at 200 and would not drop. Once it hit 220 I pulled over to let it cool. Driving back last night with cooler weather the car still was running at about 185 then hit 200 and drop back down to 185 but no cooler then that. Im guess weather at that point was about 75 degrees. It's a be cool radiator with spal dual fans.


Gray Beard Member
Front mounts restrict flow to the radiator, big time. Royal-T-LTD has given you valuable advice. I live in Phoenix. You wanna see temps climb.... ? :cool:

RMI is good too, and as grass doctor said, it cleans the system. But be aware, it will find ANY AND EVERY weakness toward a leak in the cooling system and exploit/let you know it's there by making it a real leak. That's not actually a bad thing, if you think about it.

It will, however, drop your op temps some 15 degrees, too.
Ok going to remove thermostat 1st. Was curious so went for a quick drive. Weather is 77 degrees right now and car stood at 190. And wouldn't go back down. This was on a 10mi drive at cruising speeds of 35 to 50.

No disintegrations

Well-Known Member
Who tuned the xfi? You can ask them but sometimes too much or too little spark advance can cause higher running temps. Might need a little tweak in the cruise cells.

Chuck Leeper

Toxic old bastard
Staff member
The temp on a stat, only indicates the minimum temp it will START to open. Putting a 160* stat in place of a 180, only means the point at which the opening begins, is lowered. In this case, the engine is operating at a temp well above the stat, whether a 160, or 180. A working system should run close to the stat value. { Assuming system is designed to do so.}
A ft air dam, that was intended to direct air to a rear mt i/c does nothing to control air to a f/m. It just raises the turbulence between the back of the rad, and the ft of the engine. Use of a hot air air dam has helped, in some cases.
Other items:
Details on the engine?
Under drive pulleys?
Belt slip due to bad tensioner?
Fans wired backward?
Engine block full of crud?
XFI temp control settings actually working?
AFR lean?
Cruise timing?
Data logging could help there.
Leaky head gasket?
Still running cat converter?
Exh system plugged?


Well-Known Member
Here's a thought....how about a real radiator box in kit . Bet this will re-direct a bunch of air directly to your radiator & should reduce engine temperatures substantially

GNS Radiator Box In Kit.jpg

GNS Radiator Box in Kit #20100GNS

This kit was designed to replace those flimsy factory rubber pieces around the radiator.
This kit will divert 100% of the air that travels through the grill to be forced through the radiator resulting in 10-15 deg cooler temps. Our kit is made out of 1/16" aluminum sheet that comes factory coated in a satin black.
* Very minor notching is required external coolers or intercoolers.