'87 automatic

So i was out driving a few minutes ago, its about 35 degrees out and Im keeping my speed at about 30 mph and 1300 or 1400 rpms. My car has been dying somtimes when idling, or all the time when left in drive at slow speeds ( <20 ) or idle. I just shift into neutral and keep the revs up a bit to stop it from dying while driving. So im checking all the guages while driving to try and see whats going on. My coolant and oil temp are a bit higher than usual. So i keep driving to see if they go up more. Oil hits about 225 and i start to head home since it keeps going up. Coolant is about 207 at this time. By the time i get home (about 5 minutes or so away) oil temp is at 242 and coolent peaked at about 209.

Ive had the car since May last year and when driving around town in the summer, coolant might get that high, but oil would never get that high, at the most 225 when on the highway for an hour with coolant at 190 and ac off.

Could it possibly be a vaccum leak, and more air is being sucked in after the MAF creating a lean condition to generate this much heat? Thats all i can think off... any ideas?

Here are some other problems that might be related, but im not sure.

The volts when the car is just started are at about 11.1 . The car starts right up though. After a bit of driving they go up to 13.9 while cruising, but they sink as low as 11.0 when accelerating... enough so that my stereo (though not very loud) cuts out. Maybe just a bad alternator?

Another thing is the heater stopped working. Now i would normally not think anything special of this, but now that i think about it, it seems to have stopped working about the time the car started to repeatedly die.

I don't know a whole lot about this kinda thing and sorry for the LONG post. But THANK YOU in advance for anyone that could help.

 

I would start with testing the battery, alternator and grounds. These cars don't work well when the voltage is too low or too high.
Heres some info and diagnostics for the heater/AC
Manual..http://members.shaw.ca/agent86/Air%2...0%20Manual.pdf
Electronic.. http://members.shaw.ca/dankai/AC%20Electronic.pdf

 

with AGENT 86, I'd also check for vacumn leaks, and your IAC
may need cleaning (their a carbon magnet) your engine temps sound
about right-what type of oil are you running-dino or synthectic? depending on which type-if it's dino, it starts breaking down around 250, if it's synthetic you should be good to around 300. My engine 87,
oil and temp are usually around 10-15 degrees different and I'm running dino.My engine temps run at a high of 209, same time my oil temps are right in there.

 

The reported temps aren't alarmingly high. Your lean theory is possible, but I would expect to see a check engine light. What is it about the heater that isn't working? The fan doesn't run, or it blows cold air? You could, simply, be low on coolant. That would cause the heater to blow cold air and allow it to run hotter than normal. On the electrical; I'm guessing that the alternator is marginal, or simply too small for your stereo.

RACE ON!!!

 

Yes there is a check engine light on, but not a low coolant light. The check engine light has been on since I had the car, without any of these problems. And also the heater is blowing cold air.

The oil is synthetic so it should be safe then. But its just strange to see the oil temp that high above what it usually is, let alone on a near freezing day.

So check grounds, battery and alternator. Also check the IAC and check for vaccum leaks. How do I go about checking for a vaccum leak?

 

first of all the check engine light indicates a code has been thrown-so, you need to pull codes, hope you have a FSM or at least a Haynes.

Second-you can check for vac leaks simply with a small propane torch
DO NOT LIGHT IT ! just turn it on while engine is running and direct it towards vac lines, if you find one leaking your RPMS will change.

Good luck