Hi Guys,

Thanks to you all for being active on this forum. I have really learnt a lot about my MERC ... in the past few days as a member to this forum. As always I post a few queries here for which i would like to hear from you all.

It's about my MERC 230 E (W124), but the queries are very general.

1) Is it OK to wash the engine compartment with pressurised water at a professional Wash Station. I recently got my car washed at one such place where they use high pressure hoses to clean the car including the engine compartment. After the wash i started the car and the engine revved up to 2500 rpm and stayed that way for 5 minutes. After the engine heated up the rpm came down to normal. This worries me as to weather i am hurting the engine. Please advice.

2) I live in a hot climate (40 degrees) most of the year thru. The engine temp on the dashboard shows 80 + most of the time at normal driving conditions but well below 100. Is this normal?. What is the optimum operating Engine temperature?.

3) Oil pressure gauge on the dashboard fluctuates between 2 and 3. I have to top up the oil in the engine by 1/2 a liter every 1000 kms of run. Is this OK?

4) Is the foam insulation under the bonnet supposed to reduce engine noise in the passenger cabin or is it only to reduce heat on the bonnet surface?

#1 Electronic engine controls and water don't mix. Keep the engine bay dry!!
#2 80 degrees is normal. Short periods of 100 won't hurt it.
#3 Oil pressure is normal. It may drop lower when very hot, but as long as it comes back up it's ok.
#4 The bonnet pad provides both heat protection and noise insulation.

Enjoy the ride!!

Cap'n Courageous offers good information as always.

Maybe I've been lucky, but I've kept my engine compartments washed down on all my cars for years with no ill effects. I've probably washed the engine compartment in my 124 at least a dozen times with no problems.

Good luck,

I hope that A/C works good!!

last time i washed my engine with a hose, water got into my spark plugs and wires. the engine ran very rough and worst with the A/C on. Only after lots of searching and help from this forum, i found that problem. I dry out the wires and got new spark plugs for the car. Car ran fine since. so watch out for issues like that.

As a show car fanatic, I hose down engines regularly...the tips by those who previously posted are proven, and they work!

High-pressure can also force water into crevices that would not normally be introduced to water...so beware! If it was hard to get water there in the first place, it will take awhile for it to be expelled! So if you MUST use the car wash hoses, use the "engine clean" cycle at low pressure only.

MB wisely placed the sensitive electronic controls in protected bunkers away from the areas that would most likely see water...so that is a good rule of thumb to use when you do put the hose to the engine...in other words, don't hose off the battery compartment!!

Sometimes getting water on ignition components can be unavoidable...and that's ok. Just make sure you get a towel and blot off the excess moisture on both electrical and mechanical parts, especially in places where water can pool for days before evaporating...spark plug holes make great moats in some engine configurations.

Note that after a thorough washing, exposed lubricated parts have probably had much of their lubricant washed off. I usually go and relube those components after I'm finished.

__________________
2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

I've washed many a car at the pressure wash. The one thing I've learned is to keep the engine running and try not to directly hit the distributor/coil packs unless from a further distance.

__________________
Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)

Thanks Guys for all the helpful suggestions. This is the reason I like being on this forum. Bye.

I have to fight the urge to wash my car under the hood. I have done so with other cars in the past with mixed results. My 82 VW Quantum Coupe (the only year they made the model) was the only one that gave me problems. Not sure if it ever ran the same, but I did trade it with 150,000 miles after buying new. Learned that the trick is to use as little water as possible, like a fine spray from a garden hose, not high pressure like a car wash. I think the cool engine with a little degreaser just where needed is a good idea. Then dry everything off as well as possible with a towel. I like to use a leaf blower to blow pooled water off of my exterior, especially in the little cracks and crannies. That would probably help under the hood, too. For now, I'm just using a wet rag and wiping off surface dust where I can reach it.

If you use high pressure, be careful not to hit radiator or condensor at an angle--the high pressure might bend over the thin metal fins.

__________________
Jim Wiggin
Columbus, OH
1989 300E