time to make a decision

[Ghost]

A little more back story. On the day I was driving to Fla, I noticed the temp was running about 20deg higher then normal. it went about 150 miles like that before it spiked enough to make the Check Gauges light come on. Then after a mile or so it would go back down to where it was (around 220). I thought maybe the thermostat was sticking. I stopped at a gas station and removed it, permatexed it back on. It stayed around 210 while idling so I headed back down the road. After about 20 miles it did it again.

It will stay around 210 while idling but once I get up to 60+ for 10 mins or so it will go up to 225 or so and stay there for a bout 10 mins then spike again.

I gave up and called AAA and had it towed to Savannah where we could rent a car.

It really seemed like a head gasket / head issue from the symptoms. And the fact that these 00-01 engines are known to have head issues, I felt like that was the issue.

So this past Saturday, I ended up going to Savannah and pulling the head off, cleaned everything up, and installed a new head and gasket.

While driving home today it went about 120miles and it started the same thing again. Called AAA to tow me from I-26 and I-77 to Waxhaw. So, after money spent on a head and all the stuff to change it, and 2 hotel nights. I still have the same issue.

I replaced the radiator about 3 years ago, the water pump is new.

Any thoughts on what is going on?

Is the electric fan working when it's supposed to?

 

[gray_penguin]

I know it was working but will have to make sure. Was thinking maybe fan clutch also.

 

[techno1154]

I know it was working but will have to make sure. Was thinking maybe fan clutch also.

I am not sure your problem is fan related but it is surely a cooling issue. Unless your carrying/pulling a heavy load or going up hills, the XJ should not overheat like that.

Air flow through the radiator;
At highway speed ram air should be enough to prevent spikes. Look for blocking either by the AC condenser or the radiator fins themselves.

Coolant flow;
You said the water pump is new. Could you verify it is still good? Is the radiator partially blocked or some other restriction in the cooling system? Thermostats sometimes play tricks on people.

Then there is the question of the exhaust system i.e. catalytic converter and/or is it running rick or lean?

My XJ have no mechanical fan and the temperature stays at 210 +/- 5 at all times at highway speeds.

 

[gray_penguin]

Well, I did have a fan relay issue. With the AC on and temp at 225 it was still not spinning. I removed the relay and replaced with an old one, still nothing. Put the newer one in and it started working. It now comes on at 220 and cuts off at 217.

The gauge on mine seems a bit off. the odb2 shows about 10deg more then the dash gauge.

I also managed to purge a lot of air out to the system.

Will take it out for a drive tomorrow and see how it goes.

 

[Ghost]

Swap the fuel pump relay with the e fan relay and you will know for sure if the relay is bad. Do you have a shroud around the mechanical fan?

 

[gray_penguin]

actually, the top of the fan shroud broke off. it is still on the lower 3/4 though.

I broke the original one and ordered a new one from rock auto. I managed to break the new one a couple months ago.

 

[gray_penguin]

Now I am getting a P1491 CEL code. (RADIATOR FAN CONTROL RELAY CIRCUIT)

I ran it down the road about 10 miles and it stayed at 180Deg (I have a 180deg thermostat in it).

I read on here to test the fan while the engine was running by unplugging the temp sender at the thermostat housing. When I did the fan came on.

I also read a post on here that it could be burned out "diodes" in the wire housing from everything getting so hot... ? Anyone now about this?

 

[Lowrange2]

That sucks.

It's times like these that I do a complete overhaul on the cooling system. Radiator, waterpump, hoses, fan clutch and flush everything. Warranty it all out for new stuff.

I suppose we should have discussed what it was doing before you pulled the head off.

 

[gray_penguin]

Well, I have a high-flow thermostat, new fan shroud, and new belt heading my way from rock auto. The radiator is 2.5 years old, the water pump is about 3months old, the fan clutch is about a year old.

I flushed the system out about 2 years ago when I replaced the heater core (boy was that a PITA).

I really wonder if the electric fan has been intermittently working all this time. Maybe there is some short or something loose in the circuit. I am trying to find some info on these diodes I read about in another post.

 

[gray_penguin]

I found a couple threads where the fan would work fine when cold but not when it was hot. Maybe a new fan would be the solution.

 

[Ghost]

I'm not too familiar with the ODB II stuff but on any of the jeeps if the e fan is intermittent then that could explain the temp spiking and then coming back down.