1992 300SE - running warm in hot, city driving

[86560SEL]

My uncle has a 1992 300SE with 109K miles. The car runs beautifully- I have driven it. He said when its hot out and when in city driving, that the car will run warmer than it normally did, especially with the A/C on. He bought the car brand nearly new (when it had 7300 miles) and he said it seems to creep up more and more as time goes on. I asked and he said that the mechanic said that the radiator was OK and water pump and that the headgasket was probably wearing out, but not to be concerned now, but to keep a close check on the temperature gauge when in hot weather, which is the norm here in the southeast.

I am wondering, are these engines known for headgasket problems and does it sound like a HG issue. Also, the rear end is floaty. How difficult are the rear struts to change on these cars?

Thanks.

[Larry Delor]

Well...it will run a bit warmer when it's hot out, and the A/C is on - however, how hot does it get? What does the gauge indicate? A bit of a temperature increase is to be expected/ It might be a good idea to give it a flush (search for citric acid flush).
As far as the shocks go...my opinion, just by looking at the parts, is that it is a fairly straight forward job - biggest pain would be getting to the top bolt (getting stuff out of the way/etc.), and depending on what kind of rust you might have, getting the bottom bolt(s) out. There are quite a few parts listed, depending on your VIN and what option you Uncle has for the suspension. I'd be a little surprised if the shocks were bad already...they usually last a bit longer. Check the tire pressures, and the rear sway bar links (easy replacement, and surprisingly not super expensive)

I'm sure that others with more knowledge will post their input, so don't take my words as gospel.

[psfred]

Shocks are easy, but check the tire pressure first. If he has new tires on there, the inflation pressures are MUCH higher than they used to be as everyone is going to high pressure tires now.

If you inflate a 51 psi max pressure tire to 32 psi, you will be driving on the sidewalls and it will wallow terribly. Inflate to within a few psi of the max before changing the shocks, as they usually last much longer than 200,000 miles.

As to running hot, check the operation of the visco clutch and pull the radiator and remove all the crap between the rad and the AC condenser -- we pulled my brother's this winter on his SDL, and about half the surface was packed with dead bugs. Made a huge difference this year. Also, sitting in stalled traffice at 100F with the AC on, the engine temp will probably go up to 100C no matter what -- this is the temp where the aux fan switches on.

Peter

[Hatterasguy]

If its running a bit warmer than before its probably the fan clutch and/or radiator.

Radiators lose efficiency as they age, considering how old it is its probably not a bad idea to replace it.

[Arthur Dalton]

First check is to see if the aux fan comes on when a/c is on. If not , you could be low on refrigerant.

PS



It's running....

[86560SEL]

Thanks for the replies guys. Well, he said its a little over half way. I personally think that the "mechanic" is trying to pull a fast one. I told him to be sure he has ruled out the radiator, water pump, fans, etc before paying $$$ for a headgasket. I think he was quoted $1700 for replacement.

As far as the rear struts/shocks go, I personally would not change them if the car was mine. Yeah, it was a little floaty, but nothing bad. I thought it gave the car a pleasant ride. I would be more concerned with the steering response. It seemed a little vague. Something was definitely in order to be replaced.

[Hatterasguy]

A properly sorted W140 is one of the best riding cars ever made, so something is wrong. Sounds like it needs new shocks all around. How many miles? The originals are good for about 100k.