S55 M4

SynTom · 07-13-2019, 06:35 PM

Topping off the oil today in the M4, I decided to start removing bits of plastic. Checked all the fluid levels, noticed that the larger of the two coolant expansion tanks is totally empty. Not a drop of blue coolant in there.

The tank is on the passenger side of a right hand drive car, near the oil filter cap. The smaller expansion tank at the top centre of the engine bay is perfectly filled.

My recent 420i drank a small amount of coolant but not enough to drain an expansion tank. Anyone got any experience with this?

Unsure as to buy some coolant from the shop and top it off myself, go to the local BMW indie and get them to do it for me or to ring up BMW and see what they have to say? I have 2 years of warranty and service left on the car.

Also, there is no residue on the expansion tank cap to indicate a leak from there. Does the S55 engine just sip on a bit of coolant over the miles?

Cheers,
Tom.

SenorFunkyPants · 07-14-2019, 03:06 AM

I'd get BMW to sort it under warranty.
These engines shouldn't consume any water.
The filler tank on top nearest the windscreen is for the intercooler....and a couple of peoples have found this one to be low and needing rectification by BMW.

G82Dude · 07-14-2019, 05:12 AM

...if you have service pack, they will do this for you FOC.

07-13-2019, 06:35 PM	#1
SynTom IAM Roadsmart Fellow 48 Rep 100 Posts Drives: BMW M4 Coupé Join Date: Mar 2018 Location: United Kingdom iTrader: (0)	S55 M4 - No coolant in expansion tank. Topping off the oil today in the M4, I decided to start removing bits of plastic. Checked all the fluid levels, noticed that the larger of the two coolant expansion tanks is totally empty. Not a drop of blue coolant in there. The tank is on the passenger side of a right hand drive car, near the oil filter cap. The smaller expansion tank at the top centre of the engine bay is perfectly filled. My recent 420i drank a small amount of coolant but not enough to drain an expansion tank. Anyone got any experience with this? Unsure as to buy some coolant from the shop and top it off myself, go to the local BMW indie and get them to do it for me or to ring up BMW and see what they have to say? I have 2 years of warranty and service left on the car. Also, there is no residue on the expansion tank cap to indicate a leak from there. Does the S55 engine just sip on a bit of coolant over the miles? Cheers, Tom.
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07-14-2019, 03:06 AM	#2
SenorFunkyPants Brigadier General 2511 Rep 4,381 Posts Drives: 2019 M5 Join Date: Mar 2009 Location: UK iTrader: (0)	I'd get BMW to sort it under warranty. These engines shouldn't consume any water. The filler tank on top nearest the windscreen is for the intercooler....and a couple of peoples have found this one to be low and needing rectification by BMW.
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07-14-2019, 05:12 AM	#3
G82Dude - 290 Rep 2,598 Posts Drives: M4CMxD Join Date: Dec 2008 Location: Earth iTrader: (0)	...if you have service pack, they will do this for you FOC.
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