So it's been 100/100+ degees in lovely Los Angeles these past few days. So when I put the A/C on it works fine at all times, but a few minutes later the car acts weird, the temp gauge goes up in between the red and normal, and it shakes at stop lights. I turn off the A/C and the car stops shaking, and the temp gauge stays, but whats going on here with the VOLVO? Any help? thanks.
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1991 Volvo 240 101,300

Hi, my 93 240 runs hot at idle in the summer with the A/c on too, sounds like your frying your engine.
the only thing i can think of is if the head is'nt warped, and coolent is'nt being burnt ( leaking into the cylinder)to run it in neutral at stop lights at a hight idle ( about 2000, 2500 rpm) to keep the engine cool, and keep pumping antifreeze around, while there is no air being run though the radiator.
thats what i have to do, and it works pritty well, either that or opt for a bigger radiator ( IPD has a good one).
good luck.
Rich

Could be more than just one cause....

Firstly realize that when A/C is working, cooling capacity of the engine is somehwat decreased, for reason that the condensor gets hot (due to pressurized refrigerant) and reduces the ability of the radiator to receive cool air. Of course, this is the job of the cooling fan. In theory, in a perfectly funcitoning system, this should be no issue, but couple that with 10+ years and a potentially inefficient rad, dirty coolant, bad t-stat, dirty condensor, non-functional fan, etc... and everything contributes...

Also, if you ever find your a/C is not super cold, it could be possible you are low on refrigerant. Low charged system has a harder to turn compressor, which makes the engine work harder to turn it.

One step at a time, check the obvious, like fan operation, try blowing out the crud from the rad and the condensor with a garden hose (inside - out direction), and maybe it's time for some coolant system r&r...

Enjoy,
Greg Mustang
Montreal - Ottawa
Canada

I agree with Greg-
try washing out the radiator, either with a hose or the high-pressure wash at a self-serve car wash, it could have dirt, bugs, leaves blocking some airflow through the rad and the AC condensor.
The thermostat might need to be replaced too. If the system seems to be good otherwise, chalk it up to the funky temperature gauges in most 240s. There is a compensation circuit board in the instrument cluster that can create a false "high" reading- it's about $40-50 for this part and it'll make the gauge read correctly. A lot of 240s get funny readings when the weather gets hot- we would see 10 to 20 of them a year at the shop I worked at, every spring and early summer.
Good luck!
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Rob Bareiss, New London CT ::: '87 244DL/M47- 229K, 88 744GLE- 218K, 82 245T-181K Also responsible for the care and feeding of: 88 745GLE, 231K, 87 244DL, 239K, 88 245DL, 246K

My '92 had similar problems, but in 2 stages. The horrendous shakes came because my auxiliary fan was mising two blades! Seems the P.O. was in a minor fender-bender and the fan took some damage... it was re-installed improperly and eventually shed its blades. Replacement is straightforward - about $135 from eeuroparts.com, but you may need to replace the little rubber isolation mounts at $9 a throw from Volvo.

Having just moved to Phoenix last summer, my 245 also started crowding the red zone on the temp gauge when in traffic, and I would have to shut the AC off in order to keep it in the safe zone. Most of the cooling system seemed fine, so I took a chance on a new radiator, and that made all the difference. I used the OEM plastic-and-aluminum type (hey, the first one lasted 11 years...), and I can tell you that for a normally-aspirated engine (although with a VX cam) driven in the desert at 117 F in traffic, or 90 mph blasts from Phx to Tucson on I-10, or long mountain pulls up to 9000' at 85F, the stock radiator setup worked just fine. New hoses and 'stat went in at the same time to do the job right.

Hard to say from the bare bones sketch, but the auxilliary fan is coming on for sure and sometimes some of those fans are a little imbalanced. Remove your grille and see if the fan activation (temperature) correlates. As for the engine coolant temp reading, sound normal for slow traffic in 100 degrees. So you are getting AC cooling?

I agree...I had one car that as I was moving it, I actually felt a shake in my foot where it rested on the brake pedal and my fanny on the seat, I thought, "what the hell is THAT?" then realized whenever the fan sound disappeared so did the shimmy in my fanny...hmmmm...wonder why she didn't complain about that?!?!?

The A/C stays ice cold. It was just charged a few months back. I never knew the fan would shake the car like that, I will have to check it out. thanks.
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1991 Volvo 240 101,300