190E Overheating Problems

[John Sweeney]

I was wondering if any of you folks might have some help for me with my 1988 190E. Previously, the temperature never rose more than 60 - 80 degrees. In the last few months it sits at 90 degrees constantly once warmed up (even on the motorway with the heater on full) and is accompanied by faint pinking when under load. When moving slowly in traffic, the temperature slowly heads towards 100 degrees. Having said this, the fan has only come on once while I have owned it.

I have flushed the system (extensively) and changed the thermostat, but all this suceeded in doing was making the problem very slightly worse!

Is this how it is supposed to be? Or have I missed something when I flushed the coolant? Could there be an air lock? Any ideas would be greatly appreciated!
John.

 

[Ian B Walker]

Quite possibly an air lock. Did you blead the heater? Having read both your posts I think that both topics are somewhat related.

 

[John Sweeney]

Hi Ian,

Thanks for the reply. I followed the instructions in the Haynes manual (sigh), and it mentions nothing about bleeding. How is this done?

Thanks, John.

P.S. - You might know the dealership the car was bought new from - Ciceley Continental.

 

[grober]

I have heard people advocating parking the car on a steep slope so that the radiator / header tank is the highest point in an effort to bleed the system. might be worth a try??
Remember to have
1. the heater switched to the hottest position
2.dont starve the engine of oil.

When refilling the system initially after draining fill up to the full mark on the expansion tank with the corrrect 50/50 water /antifreeze mix. Squeeze the top and bottom radiator hoses to help displace trapped air. Then run the engine at fast idle to warm up but remember to leave the pressure cap off till the temp reaches 60/70C. Top up again and put on the pressure cap. let the temperature rise to 90-100c then switch off and allow to cool. then top up again etc etc till you have eliminated the air in the system. There is also the possibility that you have a partially choked radiator, see Guy Dewdney's sprinter post.

 

[Vips]

John

I am not sure that you really have a problem!! The ideal operating temp for mercs is around 90 degrees. This is bound to rise a little especially when you are in heavy traffic. However, when on the move again, if the temp drops back down than the thermostat, fan, viscous coupling, cooling system are all working fine.

This is my view, but I'm no mechanic.

 

[grober]

bleed first

Not wishing to a prophet of doom but outside chance it might be your head gasket? Is your OIL OK? no white mayonase? or black scum in the header tank?
I would try bleeding the system as a first step !

 

[John Sweeney]

Thanks guys. This is really good advice. I'll try it all this evening. Will get back when I'm done.

John.

P.S. - No mayonnaise or the like in the oil, and no oily coolant so, keeping everything crossed, I don't think it's a blown head gasket!

 

[Dieselman]

John

I am not sure that you really have a problem!! The ideal operating temp for mercs is around 90 degrees. This is bound to rise a little especially when you are in heavy traffic. However, when on the move again, if the temp drops back down than the thermostat, fan, viscous coupling, cooling system are all working fine.

This is my view, but I'm no mechanic.

I agree here. The engine is running as it is meant to.

 

[John Sweeney]

Great!

That's the best news I've had all week! Thanks. I'll still try bleeding it to see if it makes any difference.

Kind regards, John.

 

[John Sweeney]

Guys - I've just had a thought. What could cause the pinking when the engine is warm. I've tried a course of Redex to help, but to no avail. Any thoughts.

John.

 

[GarethM]

Have you recently started using your AC again ?

My AC wasnt working ( regased now ) and my W208 sat at 80 all day long. now ive started using the AC it climbs to 90 odd when sitting in traffic.

Any help ? ( Or do i have a problem ! ( Just replaced my water pump ! ))

G

 

[Brian WH]

Guys - I've just had a thought. What could cause the pinking when the engine is warm. I've tried a course of Redex to help, but to no avail. Any thoughts.

John.

Pinking can be caused by timing being retarded, and this will cause some overheating too. But don't panic as the temperature is still within acceptable limits, as previously said.

I agree with Ian the two problems with your car are related.

 

[John Sweeney]

Hi Gareth: My car doesn't have air con, so I don't have to worry there.

With regard to your car heating up when it is switched on, I wouldn't worry - it might be normal, as the engine is under greater load when the air con is on. My old 1986 Vauxhall Senator did the same thing when the air con was switched on. On the other hand, I'm not an expert about this sort of thing. Does any one else have any thoughts?

John.

 

[John Sweeney]

Thanks Brian - you've put my mind at rest. I think I'll have the ignition timing checked soon.

John.

 

[blue190]

Sorry to sound like a harbinger of doom but don't take it for granted that no mayonnaise means head gasket is fine. just before christmas my old citroen zx was giving me all the symptoms of head gasket failure but because i had no evidence of oil/water cross contamination i overlooked it and ended up cooking the engine, on xmas eve of all days. I'm not saying that this is true in john's case but its worth being aware of.

 

[John Sweeney]

You know, you may be right - I think it might be a wise precaution for me to have it looked at by someone who knows more about this than I do! Thanks.

John.

P.S. - That's rotten luck about your engine blowing up on Christmas Eve. If it was last Christmas Eve then I can sympathise - a brand new Range Rover drove straight into to the back of my immaculate '86 Vauxhall Senator two days after I had bought it last year. On inspection the accident had only cracked my numberplate, but the damage to the Range Rover ran into the thousands, so the owner tells me (we have since become firm friends!). It just shows that they don't build them like they used to! It wouldn't have been so bad, but I had only bought the bloody thing because a bus had written off my previous car the week before while I was in the Post Office! Lecture over.

 

[shrekky]

Sorry to sound like a harbinger of doom but don't take it for granted that no mayonnaise means head gasket is fine. just before christmas my old citroen zx was giving me all the symptoms of head gasket failure but because i had no evidence of oil/water cross contamination i overlooked it and ended up cooking the engine, on xmas eve of all days. I'm not saying that this is true in john's case but its worth being aware of.

i agree with blue190 just because there isnt any cross contamination dont mean eveything is ok............might be a good idea to have it compression tested,also get water system pressure tested,because pinking can be caused by over heating too...........i have a 190 and it never goes above 80,well maybe on a really hot day and idling for 1/2 hour..lol

 

[John Sweeney]

I've never been happier! Ian Walker has very kindly sorted out my problem - it turned out that the ignition timing and the mixture were both way out (the mixture was almost off the scale!). He had one attempt and wasn't quite satisfied so he had another go. What a perfectionist - he even came to me! He spent a total of five hours on it, and let me have a go in his 260E while I was waiting - I'm a MB convert for life now!

This gentleman is the perfect forum member and has my enduring gratitude for sorting my car, which now feels like new (no, really!). All the previous problems have now gone. If he does decide to go ahead with starting his own garage, he will have me (and many others, I'm sure) as a regular customer.:bannana:

Thank You Ian!

John Sweeney.

 

[grober]

nice one!

Glad you got it sorted. Sometimes the getting the basics right is all you need! Nice one Ian.:bannana: