Can modifying suspension cause Over Heating

I have an 88' Xj with the 4.0 5spd and 231 tcase.

The suspension has been very highly modified. It has home brewed longarms based on the rock krawler lift. it sits at about 7" up or so. It has full width ford axles front and rear.

My problem is that when i'm crusing on the freeway at about 70. the temp gauge climbs to about 230 or so and will keep rising. it currently has 33" tires and 4.10 gears. so the motor isn't turning that fast. what is even more funny is that it will cool down if you slow down and cruise around town for a little while.

I know that the presure tank thing on the fire wall is cracked and i will replace it tommarow could that be the whole problem. it also doenst have a fan shroud but the mechanical fan doesn't do anything on the freeway. The electric fan is wired to a switch in the cab and is pretty much allways on.

If you need any more ifo please let me know. I'm headed to moab on friday and i need it fixed before then any one have any ideas?

TIA

Jerm S.

Yeah -- fix the pressure tank. Unless your system will hold pressure you can't even trouble-shoot it for other problems.

The open cooling syetem you have is the problem, not the lift. As the older systems start to age alot of things begin to fail on them. There are different sites out there that will show you how to change it to a sealed system. I believe there is one on madxj.com. I would also put in a GDI radiator if you decide to go this rout. Hood vents help out as well.

There is a Moroso pressure tank that can be use for you current system as well. That I've heard good results from. I believe Eagel has been running one for a while. You might ask him about this mod.

Big Bear, not to nit pick, but we need to get the terminology correct. His current system is the closed, and the GDI setup is the open system.

Jerm, while your motor isn't turning that fast, it is working harder to turn the much increased rotational mass and added mass of armor.

Eagle is correct though, you need to fix the current problems you know of to diagnose it correctly. Since your system has a crack in it now, it can't do its job like it should.

Sean

My bad, I new that. My problem is I think way faster than I hunt and peck. But I am pretty sure you got the idea.

I'm not too sure about the fan not doing anything at highway speeds. When travelling at speed, your rig is pushing a huge amount of air. This is a high pressure area in front of the grill, bumper, etc, and air will take the path of least resistance, which isn't necessarily through the radiator. When the fan is turning, especially when the fan clutch is loked up, you are creating a low pressure zone behind the radiator. This will help the air flow through the radiator.

This is just a theory of mine. Feel free to tell me I'm full o'crap.

Dan

BTW, These guys are exactly right about keeping the closed cooling system "under pressure.'

Dan

OneTonXJ said:

Big Bear, not to nit pick, but we need to get the terminology correct. His current system is the closed, and the GDI setup is the open system.

Click to expand...

Sean, my man, if you're going to pick nits at least do it accurately.

The old style system is the "closed," the new style system is the "open." However, GDI is simply a radiator manufacturer, and they make 3-core replacements for both styles. In my '88 I installed an "old-style" GDI radiator plus I replaced the crappy OEM plastic tank with a Moroso aluminum tank and an after-market overflow/recovery bottle. This increased the total capacity of my system, removed all air from the pressurized part of the circuit, and allowed me to keep all the original sensors, senders, and heater valve setup with no concerns about finding a way to actuate the aux fan.

modifying the suspension causes death wobble