Alright, this is my first summer with my XJ. Bought it last September from a friend. I knew they ran hot b/c while it was his we did some upgrades trying to help it run cooler in traffic. Drilled some vent holes in the t-stat, HD aluminum rad from the government models, trans cooler, and removed hood heat shield. Since i've gotten it i've wired the factory electric fan so that it comes on with the A/C or I can flip a switch to turn it on. That alone keeps in at 210 sitting still on most days. But if you're sitting in traffic with the A/C or if the temps above 90 or so it still wants to get up to ~235. Systems purged, t-stats good, coolant full.

I'm curious if providing a way for the heat to exit the engine compartment easier would be beneficial. Is there any vents I could install that look at home on the XJ and won't allow water to get inside? I looked in the "stick-on" isle at the parts store and didn't see anything attractive but stuff I could make functional. I am also considering ditching the clutch fan and putting a second electric fan on. I know it was majorly beneficial to my SS when I ditched the clutch fan and installed dual electric fans. So whats a good junk yard swap in? Can I get another electric fan from a XJ and put one on both sides and it pull enough air?

Also, we removed the carpet just before I bought it, spilled milk and a hot day. Now that its summer the heat from the trans tunnel is rather uncomfortable, so whats a good cheap heat mat that I can put on the tunnel. I know Dynomat but i'm wondering if there's something cheaper where you're not also paying for the name.

Lastly, how hard is it to replace the lock-up solenoid in the trans? Its a 96, I know the trans were different on various years. The heat has finally killed the solenoid.

 

labaron hood vents are what a lot of people use and i saw someone recently use grill material and just cut the hood and put this under which looks awesome and I think that people use the turrus electric fan but not sure of the year..

 

First if the T-stat has extra hole in it it is NOT good. Part of the function of the T-stat is to HOLD the fluid in the radiator so the the air flow can cool the fluid.
The main E-fan should come on at 212 degs or when the AC/Defroster is on. The mechanical fan is more efficient than any dual E-fan setup I have heard of in the cooling area. It is capable of higher CFM than most if not all e-fan setups. That is provided the Clutch is functioning correctly. there are write-up for swaps to the ford torus fans and even Dodge Neon fans.

 

The t-stats in both of my vehicles have two 1/8" holes drilled in opposite sides of the stat. It lets any air that may have not been purged from the system be passed when the system is being purged. Something we've always done and has always worked better for us. The real purpose of the t-stat is to hold fluid in the engine so that it can run to up to optimal temperature in the winter and not be too cool. All the t-stat does is control the lower temperature level. On these Jeeps, once the engine temp gets above 195 the stat never closes and theres a constant flow. The fan clutch has been replaced and is in proper shape. When you turn the fan by hand it stops after only a 1/4 to 1/2 revolution.

I've been looking through alot of threads at vents. I dont like the idea of having openings in the hood for water to drain in the engine compartment. Yes, the engine compartment is open to the elements but under normal circumstances it is not open to water flow, only a splash hear and there. I'm thinking of venting to the cowl area, or maybe finding something that resembles a low height scoop mounted backwards on the hood like the ones on Wranglers cowl area.

 

Some factory t-stats come with a bleed hole and the sole function of the t-stat is to control MINIMUM coolant temp, not to slow coolant flow, like 84SS said. If you HOLD the water in the rad, where's that hot water that's in the block/head going to go? Don't want to hold it anywhere, you want it to circulate as fast as possible thru both the rad and engine. That's why there's some aftermarket HI-FLOW water pumps available.

The main problem with the XJ cooling system is the DINKY radiator. Come on Jeep/Chrysler, what's up with a rad that not even 12" tall????? DUH. Between our 4 cars and 3 motorcycles, the smallest radiator is 2.3 sq. in. surface area/engine cubic inch displacement. The XJ rad is <1.3 sq. in. surface area/engine cubic inch displacement.

 

my tstat closes at 195

 

Yes, it is closed at 195 and below, so if the t-stat is accurate and the engine is at 200 degrees, then it is open. So once the engine gets above that rating, it never closes again until you shut the engine off and it has time to cool. This is not the case for every vehicle but it is for XJs since they commonly run at 210 or more.

But back on topic, yes I agree with the dinky rad. The guy thats building my th350 for my SS is a tranny tech at a Chrysler dealership. He said he knew someone that cut out the bottom of the core support that rad sits on and lowered it with flat stock to put a taller rad in it. I have considered doing this after I get myself a welder.