XJ getting hot.........

[Roundeye]

Hey all,

Damn, it's been a while, I've been off-line (upgrading). Anyway, the 'ol 87 XJ is not maintaining proper temps. I installed a 180 degree thermostat during the winter and it maintained 180 most of the time. BTW, I have an AutoMeter Phantom gage that IS KNOWN acurate.

Well, it's starting to warm up around here and it has been running near 200 degrees lately. Here is what has been changed: NEW radiator, NEW water pump, NEW hoses, NEW fan clutch. I took out the thermostat for troubleshooting purposes......still she runs around 200 degrees with an outside temp of only 70. Withe the electric fan on, it runs around 190. It really likes to get warm at idle after a highway run. (A little bit is normal, but I'm talking about 20 to 25 degrees that takes a WHILE to cool back down).

Timing has been checked and fresh coolant is at proper level. I'm out of ideas. The last thing to do is change the @&^%ing head gasket :x I'm not losing any (noticeable) coolant and I do not see any oil in coolant (or vice-versa) but that does not always guarantee a good gasket.

Is there anything anyone can think of before I yank the head?

BTW: It's a 4.0 I 6 with manual trans.

Thanks in advance!
J

 

[whiterubicon]

Do a block test. Do a pressure test. A block test will test for exhaust gas in the cooling system. A pressure test will check for compression gasses in the colling system. also pull the plugs and check for one burning water. It will look like it has been steam cleaned.

 

[KellenNold]

Isn't it supposed to run at 210??????????????

 

[MudderChuck]

Around 200-210 is normal operating temp. at the gauge sender at the back of the block top. In line sixes arn´t really known for coolant to cylinder leaks, but heck anything is possible.
A couple of things that have caused me grief in the past, are a pin whole leak, leaks enough to loose a little coolant, hardly noticeable, doesn´t loose enough to leak drops, usually evaporates before it hits the ground. When the motor is stopped, the cooling system goes into a slight vacume, sucking a little air into the system, through the pin hole leak, after a number of hot/cool cylces the air adds up to enough to be noticeable at the gauge. The pin whole leaks, are usually found by a slight white crust, where the leak is, sometimes a slight stain to match the color of your coolant. Heater hoses, the connection at the bottom of the surge tank, the thermostat housing are some good places to look closely at.
A coupe of tip offs, to a coolant to cylinder leak are an unusual amount of bubbles or foaming in the coolant (surge tank). Sometimes at start up the exhaust throws some condensation, if the condensation has a tint to match your coolant color, it´s a tip off. I have also pressurized the cooling system with compressed air (or a bicycle pump) (20 PSI or so, not to exceed 30 PSI), the pressure bleeding off, is an indicator something isn´t right, Takes awhile for it to bleed down, loss of pressure is just an indicator, difficult to get a perfect seal.
Have also, pushed some strips of clean white rag into the cylinder hole, pressurized the system and checked the rag for a color stain, red green whatever color coolant you have.
V-8´s seem to have much more problem with leaks from the water jacket into the cylinder than the I-6.

 

[TwistedCU]

Jeep Culture

still she runs around 200 degrees with an outside temp of only 70. Withe the electric fan on, it runs around 190.

I've had some vehicles that ran hotter than that without any trouble. Unless the thing is overheating I wouldn't pull the motor apart!