engine overheat with A/C

[Brian1973]

Issue is engine seems to really get hot when A/C is engaged... especially if it's in the 90's outside... in the past I had to actually pull off highway once when hauling a slightly heavy load... engine was laboring as well.... Know sitting still doesn't help but it sure seems to happen more over past few years... I replaced radiator last year thinking I don't remember last time I replaced it. Figured it would help but I haven't noticed a difference... fan works fine, antifreeze is fresh, rise in temp seems slow and steady... I swapped engine a few years ago and seemed same issue as before and I know I replaced thermostat at that time as well as water pump.... is this just an issue with this engine? Any ideas to resolve? This engine is a dog to begin with but that A/C compressor really steals what little power there is! uhg

 

[adsm08]

The AC makes a lot of heat right in front of the rad. A lot of vehicles around that era had a note in the owner's manual to shut the AC off if the engine temp began to rise.

 

[RonD]

No, no engine should act that way, usual warmed up coolant temp should be just below 1/2 on gauge, and it can go up to just above 1/2 when heavier loads are involved or going up a long grade.

Any codes in memory?

EGR system helps lower cylinder temps when engine is under load, it is there to reduce NOx levels which sky rocket with cylinder temps, the exhaust gases mixed with air/fuel helps reduce the higher temps.

What do the spark plugs tell you?
A leaner mix will run warmer.

There is often an e-fan on the AC condenser in front of the rad, is it working?

Is it an automatic?
Adding a second trans cooler will help trans and reduce heat transfer to rad.

On my '94 4.0l the heater core is part of the coolant bypass system, no heat control valve on either heater hose, core got partially plugged and I got random heat spikes, never HOT, above 3/4 on gauge, but temp would go up and down.

 

[fixizin]

Might be just another Band-Aid, but... have you tried running fully synthetic oil?

http://therangerstation.com/forums/showthread.php?t=161677

 

[ranger1997]

Fan shroud in place?
Air flow problem getting past condenser?
Timing retarded will cause engine to run hot also.
How much of a dog is it?
Blockage in exhaust.




Sent from my iPhone using Tapatalk

 

[Rearanger]

Might want to see if you can get more cooling rows in the rad. RockAuto lists rads W/O AC, so maybe you have the wrong rad?? They also list a 1 row and 2 row rad.

Is this auto trans? If so then maybe a trans cooler as RonD has suggested would help lessen rad load.

 

[JP02XLT]

Rangers are also well know for trapping debris & dirt between the radiator & condenser, I would take a look at that and wash it out with a garden hose

JP02XLT

 

[Brian1973]

I think adsm08 has it right and is how I've been thinking... It does not happen on the highway normally, but this one time it was after VERY hot temps (90-95?) and hauling a hitch caddy with a generator and separate window unit AC for dogs in the cap ;-) Not a huge load but this certain spike was just after a long incline on the highway so I'm just thinking alot of different issues all together caused it. Gauge was just about to HOT and could feel definite loss of power! But, it will normally rise past halfway on the temp gauge if temps in the 90s and I can feel the heat coming out of the engine on the floorboards! Or if sitting in driveway, definitely appears to be on it's way to overheating... Just figured I'd see if this is a condition most get with this engine... I have a 2000 4Runner that never has an issue with AC running while I'm pulling a 3000lb boat. I do recall when this one instance happened I did have one plug boot that was arcing very occasionally due to an exhaust leak at the manifold that had melted some of the wire so I will add that to the issues as well Still runs hot though since that happened... It just seems a generally HOT engine when the AC gets turned on...

It is a manual so obviously, no tranny cooler... No codes... no radiator or exhaust blockage (replaced CAT few years back), shroud fine, no e-fan, fan looks good and clutch appears to operate correctly.

Couple things that come to mind as I read your possible answers though... This used to be a 91 3.0 engine (which I honestly always felt got pretty hot as well) and I remember when going for spark plugs, always having to tell the auto parts person that my engine DID specifically call for Platinum plugs in the owners manual... seems their computer always called for copper.... I've since swapped the engine to a 92 and to be honest, not sure if I've ever questioned the results I've been given since replacing the plugs now. The engine doesn't run hot any other time except when that AC compressor is running.... Would there be a cooler plug I could use?

Another option is something with the AC? this is R12 refrigerant (if it matters at all) and I have some if low but haven't checked it lately with a shop. The AC compressor seems to run about 1 minute, then shut off for about 10-15 seconds... then run again. Seems ok to me... dryer has moisture on it and not frozen... love nice cold R12.

Again, I come back to original idea and that is, just need to turn off the AC if engine becomes too hot whether from not moving or from too much load for this dawg of an engine... older cars just seem to have that issue at times that maybe current engineering has resolved? again, not happening all the time, but under right circumstances, does. I always thought just the load of the compressor causing it but yeah, makes sense the fluid going through the condenser is pretty hot and that residual air is being pushed right back into the radiator.