W463 300 D running hot

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mud
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Hi everyone, the sudden warm weather has caused my G to run hot. I had the thermostat and water pump do e a few months ago along with all the pulleys and belts and in the cold she warmed up nicely and the heater worked well. Now the temp climbs to just below the top bit of blue on the gauge and the fan is on . This happened tonight after just about 4 miles up a steady incline with normal driving. The car had been parked all day so it was stone cold. It's making me a but nervous to be honest, I have heard mention of a cooler thermostat and a different water pump pulley? No coolant loss at the moment. Any help would be much appreciated! Thanks!
markhowes
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Re: W463 300 D running hot

Just had a similar problem - although mine is petrol so probably a completely different thing but check this as it has some good tips for checking if your fan coupling is OK.

http://www.gwoa.co.uk/content/300ge-running-bit-warm

Mine wasn't and I've just replaced it with a new one since when temperature guage sits exactly where it should - and today was a very warm day.

Arnie
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Re: W463 300 D running hot

switch off the engine when hot and see whether you can rotate the fan by hand. if so, you may have a worn-out viscous coupling.

Which fan is 'on' do you have air-conditioning?

If you are referring to the main engine fan, then this will tend to rotate, but with not much force, until the temperature rises and the viscous coupling locks up.

 

...or do you mean 'top of the red' instead of 'blue'   ?

 

 

 

 

 

scouse g
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Re: W463 300 D running hot

try Rick on german ebay.de (g-ologe ebay name) he can supply you a smaller pulley (spins quicker) and a water pump with and a water pump with a bigger impeller 

mud
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Re: W463 300 D running hot
Thanks for the pointers everyone, I can turn the fan by hand when it's hot. I can hear it whirring when she gets hot. Could this really be the issue and can anyone suggest a fix please? Thanks
Arnie
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Re: W463 300 D running hot

Hello,

If you can turn the fan by hand when the engine is hot, then the most likely problem is the viscous clutch. for the fan.

The part is available from Euro Car Parts and this post, in the link below, as highlighted by Mark, will tell you all you need to know to replace it:

http://www.gwoa.co.uk/content/300ge-running-bit-warm

 

 

markhowes
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Re: W463 300 D running hot

In the end I gave up the idea of doing this job myself. There is very little room between the fan and the radiator so I was worried that I would either mess up the Allen bolt head or damage the radiator so left it to my garage to do when they did the annual service.

Very glad I did as they only charged me an extra £20 plus VAT so money well spent and knuckles saved.

scouse g
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Re: W463 300 D running hot

http://www.ebay.de/itm/Mercedes-G-W460-W461-W463-Turbo-Diesel-Improvement-Kit-Verbesserte-Wasserpumpe-/161656376174?
 

Pistonhead
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Re: W463 300 D running hot

If memory serves me right there are two temperature settings for thermostats available, which leads me on to ask which temperature setting did you fit? Is your vehicle over heating or just showing increased coolant temperature? Have you replenished with a 50:50 mixture of coolant when doing the thermostat change and as ever, I do not suppose the block was fully emptied when replenishing coolant on the last occasion.

Secondly, Arnie is correct in pointing you to look at the viscous fan but equally important to check is for Radiator blockage. I accept radiator blockage overheating would manifest in cooler climes but the warmer weather could be the right formula over heating to show up and in particular under load. Diesels' do have a temperature increase under load but as long as the reading does not top 120 degrees centigrade. That is not over heating.

To continue with the point I was trying to make is check out for any cool spots on the radiator after a good run. Switch off the engine and Carefully, with the back of your hand feel the whole surface of the radiator top to bottom and across the entire width to feel for any cool or cold spots. This would indicate blockage in that area of the radiator contributing to your issue.  a warm radiator all across indicate a properly following radiator therefore no issue there. 

mud
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Re: W463 300 D running hot
Thanks everyone, I'm still investigating but I think it might be the sensor. I've changed it tonight and will see how it goes. I'll update shortly. Cheers Mud
mud
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Re: W463 300 D running hot
Well this turned into a bit of a saga. I changed the sender which made no difference. I flushed the rad which model a small difference but was obviously severely clogged so I changed it. This took almost a month as the first 2 rads came damaged, albeit cosmetically. I've fitted an electric fan, but that has turned out to be faulty! I am going back to the standard fan when it arrives! Lesson learnt! I'm amazed, I've never had a car which couldn't keep itself cool under normal circumstances? Cheers Mud
bigblock
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Re: W463 300 D running hot

mud wrote:
............ I'm amazed, I've never had a car which couldn't keep itself cool under normal circumstances? Cheers Mud

 

It could if it didn't have a broken fan !! cheeky

Russ280
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Re: W463 300 D running hot

I ditched the viscous fan years ago as I found the noise really irritating.

 
The electric fan hardly ever cuts in, no matter how hot the ambient temperature is or how hard it's driven. That applied to the old 603 engine and perversely the 606 runs too cool.
 
So imho you still have and underlying problem. Water pump maybe?
The water ways through the head are huge so I'd be surprised if they were clogged.
Russ280
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Re: W463 300 D running hot

I've had a couple of diesel engines with failing head gaskets that haven't displayed the usual symptoms. 

 
Maybe worth throwing in some k seal type stuff? Nothing to lose.
mud
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Re: W463 300 D running hot
Hmm, well there is no coolant loss and the water pump was done in March along with the stat. I've changed the stat again last month with no change. I would have thought with a new rad she should be able to stay cool. I've also changed the sender and that also made no difference. Maybe i should revisit the pump, is there a better one available? Thanks!
mud
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Re: W463 300 D running hot
Had o bit of a think this morning, the only thing I didn't do was the water pump and stat which were done by the garage. I have had the stat out and changed like for like but, I suddenly thought could it be in the wrong way? Anyway I've swapped it around and will be taking it to work shortly. I will report back later tonight. Fingers crossed!
mud
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Re: W463 300 D running hot
Sorted! Flipping garage had put the stat in the wrong way! happy to have her back to normal, just annoyed with the garage! Cheers Mud
JASONGDS
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Re: W463 300 D running hot

No side effects to running hot for that time? I hope you have another garage for future use!

mud
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Re: W463 300 D running hot

Hi Jason, luckily she has only been to the station and back a couple of times in the last few months. She hasn't actually gone into the red as I've watched the gauge like a hawk! Probably done 20 miles in total as I've been away and using the bus and the wife's car where necessary. I've also changed my garage! Cheers Mud

leo
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Re: W463 300 D running hot

What is the correct way to fit the stat? Mine is running hot as well and I have tried pretty much everything to resolve but without success?

 

Leo

mud
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Re: W463 300 D running hot

Hi Leo, as you look at it the main body of the stat should fit into the housing attached to the bottom hose. The flat ish top with the thin dome strip should go against the engine block. There is a small notch on the stat which lines up with a piece that sticks out in the housing. I hope this makes sense? Check your fan as well. I also changed my sender and flushed it lots! Cheers Mud

leo
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Re: W463 300 D running hot

Much appreciated thanks - mine too is the wrong way round

 

Leo

mud
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Re: W463 300 D running hot
Delighted to help mate, glad it made sense! Cheers Mud