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I have a 1991 240 and she has been running hot when sitting in traffic or climbing long steep hills. She also tends to run hot when I run the A/C. She never actually overheats....but the needle on the temperature gauge almost reaches the red each time this occurs. The temp drops again when I start to move again or decend the hills. Could this be a radiator problem? It is the original Rad and the car has 180,000 miles on the clock.
Also, in a totally unrelated issue, she occasionally hesitates when I depress the accelerator to take off. It is very subtle, but it does concern me. I am thinking that I need to replace the fuel filter....but I could be wrong.
Thanks!
LSUROB
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posted by
someone claiming to be Bond. James Bond.
on
Sat Apr 17 06:20 CST 2004 [ RELATED]
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How old is your water pump?
I've heard of pumps that ran forever, never blowing their shaft bearings, never needing replacement, until...
Eventually crud in the coolant wears down the impeller blades until the pump isn't moving enough volume to keep the engine at spec temperature under high load or when idling in hot weather. The temp creeps up, then sinks back to normal depending on what the car's doing.
A well-equipped shop (dealer?) would have a flow meter to check the output.
Good luck.
Doug Harvey
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posted by
someone claiming to be Manolo
on
Sat Apr 17 05:18 CST 2004 [ RELATED]
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If your hills are steep so climbing them means slow speed, I agree with the fan clutch diagnosis.
If you have a cat in your garage like I do, you can have a pound of cat hair in and between your radiators (like I do periodically).
Think of replacing your radiator soon as preventative maintenance. The original plastic/aluminum radiator on my 1991 failed two weeks ago. Failure mode is the top hose nipple crumbles with no warning, and the top radiator hose comes off and sprays coolant all over the place. Happened to me on the way to the airport. You DON'T want that to happen when your wife is driving, (or when you are on your way to the airport).
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check the center of the radiator, opposite of the fan clutch. it should be as hot as the rest of the rad. the fan clutch needs this heat to lock up. if it doesn't, you need a clutch. if the rad is cool in the center, then you need a rad. i'm betting you need a fan clutch, because it only does it in traffic and a steep climb. running the interstate draws enough air across the rad for things to be normal. good luck, chuck.
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posted by
someone claiming to be JimL
on
Fri Apr 16 07:44 CST 2004 [ RELATED]
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Replace the thermostat - most likely problem and only $10. You can flush the radiator out with a garden hose while you're at it.
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When thermostats fail, most do so in the full open position which would cause the car to run too cool. Not a bad idea to replace it while the coolant is drained...especially if you're unsure of it's vintage.
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Your overheating problem certainly could be radiator related - I would take the radiator out and flush it inside and our with a garden hose. I have also seen many cars with a build-up of junk between the A/C condensor and the radiator, so flush the external fins of both very well.
I would also flush the engine block and refill with fresh coolant.
Since it is overheating when climbing hills, I would not suspect the fan clutch, but it is possible that the clutch is bad. You can test this by driving the car to get it up to operating temp, stop and open the hood (with the car still running). Try to stop the fan with some rolled up newspaper (you're still wearing the saftey glasses you were wearing when you flushed everything out, right?). With the car cold, it you should be able to stop the fan blades relatively easily with the newspaper. With the car hot, it should be more difficult to stop the fan blades. If it isn't, think about replacing the fan clutch. HTH
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posted by
someone claiming to be Chrissij
on
Fri Apr 16 11:43 CST 2004 [ RELATED]
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I'm opting for radiator or front cooling fan, since you have what would normally be considered an airflow problem (sitting in traffic), and a coolant flow problem (climbing hills). Of course what does the air have to flow across to cool your coolant while sitting at a light? The radiator. It is either blocked with ALL kinds of goo from bugs, pollution and such, or it could be blocked by a stationary, non-turning front fan. The relay by the coil is your power for that fan. I'd clean, clean, clean, flush, flush, flush, and check the fan for normal operation.
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or perhaps it might be a bit easier to stop the engine completely once it's good and hot, then with ignition off and fan not spinning, try to give the fan a good spin by hand. if it spins more than a full revolution, I'd look into replacing the clutch. on mine, it spins less than 2/3 of a full revolution. the idea being that when the fan clutch is warmed, and should be locked, if there is little resistance to freewheeling of the fan, then it won't turn at the proper speed when the engine is going, as the fan will still be freewheeling, and therefore not drawing much cooling air through.
another good thing to do is check the radiator temps, by feeling the fins themselves... again with the engine off. if the heat is only felt at the top 2 inches or so, and the rest of the radiator is cool, that's a good sign your radiator isn't flowing well, and should be cleaned or replaced. check this, for further reading... cut and paste, sorry, not technowiz...
http://www.troubleshooters.com/tpromag/200210/200210.htm#_HomeAtLast
this described my car's overheating problem quite accurately. I then replaced the radiator with a new nissen 3 row unit. can't complain, as I got 15 years out of the original metal and plastic one. good luck,
Link
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Your method of testing the fan clutch is probably better.
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had the same problem with my 240,then the radiator cracked waiting to pay the toll on the George Washington bridge.Changed the radiator for a copper and brass 3 row.Now it always runs cool even in traffic or with the a/c on.Changed the water pump,thermastat,fan clutch,even added a fan in front of the radiator that switched on with the a/c.But it was the radiator replacement that did it.Change yours before you are stuck in the Bronx in a shady neighborhood.
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Thanks for the advice. I live in Manhattan and would hate to break down in any area of the city...but the worst for me would have to be breaking down in either the Holland or Lincoln Tunnel. With the different suggestions that I have received with this question, I have decided to replace everything since it is all original. I ordered the water pump, thermostat, fan clutch, and hoses this morning and I found a Nissen two row all metal heavy duty radiator on E-bay for $140. Not too sure if that is a great rad....but will do some checking around before I buy it.
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posted by
someone claiming to be Chrissij
on
Sat Apr 24 07:02 CST 2004 [ RELATED]
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It's a fine radiator...we generally put in the three rows...but we are in Florida. Also, a 91 should have the front condensor cooling fan, not just the fan clutch...make sure that is working. I've had them lock solid on the front and create a really large air flow restriction. Also had one, just one, that caught "on fire" because of it...the fan relay was saying, "turn on", the fan was saying, "I can't", the relay said, "you better", the fan said, "I told you, I can't", the relay said, "sure you can", the fan said "NO", and the relay smoldered and caught fire. So, just make sure the blades spin.
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