Jmatt92

I've changed my radiator, water pump, thermostat housing, thermostat, freeze plugs, and still can't get it from overheating. Any opinions on what to do next

PocketsEmpty

Fan clutch? E-fan working? Test for head gasket perhaps?

andrewmp6

Are you sure its overheating not just a gauge reading wrong?

mitch500

Did you burp the cooling system from any Air pockets stuck inside... Jack the nose up as high as possible or park on a incline and run the motor... Add coolant if the level goes down....

Also how do you know it's over heating? Is it boiling over? Are you going by the gauge?? Put a IR gun on it and see what the actual temp is if your going by the gauge.

Jmatt92

It has a new fan clutch to. And electric is working but by the gauge it starts to over heat. I can crank it and let it run for about 30 to 45 minutes without the thermostat in and it still goes over 210 then when I hold the throttle for a minute it goes down until I let off then back up

djb383

Is it a new radiator and is the fan shroud intact/in place?

Roler

soo.....has this been solved yet?

Jmatt92

Well I flushed it out with water a couple times then used prestone then ran vinager through it and flushed one more time and haven't had time to to fill it back up with anti freeze but didn't over heat after the first flush

BlueRidgeMark

Have you verified that your water pump is actually pumping a sufficient volume of coolant?

If the fins are half eroded away, you can flush til the cows come home and still overheat.

Roler

Did your year ( I know mine does) need a reverse waterpump by any chance and if so, do you have the correct pump...?

Its remarkable, that you (OP) state that temp comes down when you put the throttle down (I guess you mean here you increase the rpm's). thats suggesting a proper working viscous fan/ clutch with flow through the radiator and open thermostat.


BUT:There are a lot of questions in this thread that never got answered by the OP. Including verification of the temps when the gauge states overheating..

It would be helpful to get some answers first before further trouble shooting...
The cooling system is not overly complex....but there are a few weird causes for overheating possible..

Anony

Radiator cap? New radiator caps have been known to leak and cause overheating conditions.

Overheating can be the result of multiple problems. Engines run too hot because of emissions, incorrect a/f ratio, serpentine belt slippage, bad pulley, a/c clutch, etc.

Here is a thread that lists some of the causes of overheating.

http://www.xjtalk.com/showthread.php?t=544

Roler

Yes, radiator cap.
A poor sealing cap will loose the PSI's that are used to increase the boiling point. An old cap can leak, and yes a new cap can leak too. Although this is far less likely. Mine appeared fine, no leaks around the radiator filler area, however a replacement cap was 10x tighter, and I have no doubt it seals a whole lot better than my old one...

Anony

My xj use to have overheating problems. After doing some repairs and parts replacements. Temperatures normally stay below 200, around 195 while on the highway.

After installing a manual override switch, when flipped on at around 210 while in heavy sand, average engine temps are kept lower and engine cool down time is significantly reduced. This is also true during other types of loads such as towing, etc.

Under certain types of load conditions the PCM aux. fan setpoints keep the engine running hotter. There may be a reason for running the engine at higher temperatures while under load conditions. I prefer to run a high mileage vehicle with aging parts a little cooler. The crossflow cooling system has a tendency to sometimes overheat while running at optimal higher temps.

50/50 mix antifreeze coolant boiling points.

0 PSI 225 deg. F.
15 PSI 265 deg. F.

scottmphoto

Is the fins on your A/C condenser blocked? If air isn't flowing, it isn't cooling. You could always get rid of the under hood insulation and put in some hood vents. Our 4.0's run hot and that insulation holds in a lot of heat. I noticed a difference in temp (by the gauge) when I got rid of mine. Hood vents are going in soon. And, I also got rid of the condenser. My A/C didn't work when I got it and I work out in the woods and never use it anyway. It lets more air flow through the radiator. Also did the ZJ fan clutch upgrade.

BlueRidgeMark

Still waiting for some basic answers from the OP.....