trevs xj

does anyone think that my ac condensor could be effecting my engine temp 25 degrees? when i drive in the 100 degree heat home on the freeway it gets to 235 with the ac on but when i shut it off it goes down to 210 which is normal. any thoughts on this?

superj

its very possible man. the ac puts extra strain on the engine when its on, thats why you can feel when the compressor comes on.

trevs xj

but do you think a 25 degree difference should be the case?

96_xj

yup that is right.

mine goes from 200-205 to 230 range when going up hills with the ac on. i run a mechanical gauge so i know its accurate.

i turn off the ac for a bit and i have my e-fan on a 3 way switch so i can run it manually on. it drops back down


when i the last time you did a coolant flush?

it should be done very 6 months

trevs xj

i just did a coolant flush about 3 weeks ago so the fluid is good and i changed my thermostat the other day because i thought it might be the problem too but it wasnt that

96_xj

also, when is the last time you had an AC recharge.

If the r-??? is bad in the ac system it does not operate as well as it should causing your compressor to kick on more than it should putting more strain on the engine

96_xj

what color was the coolant when you flushed it?

any cooling system upgrades?

djb383

Modern a/c compressors place very little load/strain on the engine. However, the condenser gets very hot when the a/c is in use and the dinky XJ radiator has a difficult time coping with that extra heat. If 235F is actual coolant temp at highway speed, your cooling system is not up to par.

trevs xj

hmmm thats something i never thought of since it blows cool enough idk if its ever been done to be honest. im not the first owner so im not sure if it was done before me.

trevs xj

djb383 i have a new aluminum radiator from ff dynamics with triple threat electric fans but i guess the condensor could still be getting too hot for even that

trevs xj

96 xj my fluid was green and brown due to some coating on the inside of the radiator im told cause its still green so it wasnt a head gasket prblem there isnt even a hint of brown anymore
and ive just got a new radiator as stated above

djb383

Unless your new ff dynamics rad has more surface area (taller/wider) than the stock XJ rad, it's still small. At highway speeds, there's more air available to flow thru the condenser/radiator than any electric fan can possibly draw. In fact, a running electric fan can restrict air flow thru the rad at highway speeds. Most electronic efi/ecu equipped vehicles have a vehicle speed sensor (VSS) that turns off electric rad fans when X + vehicle speed is reached and/or engine coolant temp is below X degrees and/or a/c high pressure is below X psi.

Unless you have a defective a/c high pressure switch, I don't see how the condenser can run any hotter than normal, presuming the exterior is not plugged up and/or lots of fins are folded flat. Again, if 235F is actual coolant temp (not what the factory idiot gauge displays), that's a little too toasty at highway speed.