ML270 CDI W163 coolant light on but coolant level OK...

[jph77]

hi there, hope someone can help....

the coolant warning light has come on and the car has lost power (i assume this is limp mode), the coolant level is fine - any ideas what it could be?

Here's hoping for a simple DIY fix

cheers
john

 

[jay1983]

Limp home mode could be anything from maf to turbo. Need to get it on a STAR diagnostics machine.
As for coolant light there is a maxi fuse on the positive terminal of the battery. When these blow they cause the light to come on. It's held on by a big red plastic nut. It's only £5 from dealer. If your unsure if it's blown or not change it anyway.

 

[jph77]

Limp home mode could be anything from maf to turbo. Need to get it on a STAR diagnostics machine.
As for coolant light there is a maxi fuse on the positive terminal of the battery. When these blow they cause the light to come on. It's held on by a big red plastic nut. It's only £5 from dealer. If your unsure if it's blown or not change it anyway.

cheers
are you saying it's not the coolant light that's causing the limp home mode?
i replaced the MAF sensor 2 months ago.
i'll get it on the diagnostics anyway but the thought of it being 2 problems isn't good.

 

[jay1983]

Tbh I can't see the 2 being connected. I strongly believe the coolant light will be the fuse.
Limp mode could be resolved by something as simple as cleaning the egr valve. Intake manifolds are also a weak point on ml270. Damn pesky swirl flaps.
Plenty of info on here tho and once you have codes am sure members on here can assist further.

 

[panason1c]

As above, small, square shaped fuse on positive battery terminal, other symptoms when this fuse blows is that the heated seats dont work (the seat led just flashes a few times) and also the engine cooling fan doesnt work either.

Limp mode sounds like a separate issue to me.

 

[Jane270ML]

+1 ^
Re limp mode... did you replace the MAF with a quality version or cheapo?

 

[jph77]

As above, small, square shaped fuse on positive battery terminal, other symptoms when this fuse blows is that the heated seats dont work (the seat led just flashes a few times) and also the engine cooling fan doesnt work either.

Limp mode sounds like a separate issue to me.

heated seats not working, LEDs flashing as you describe
i'll replace the fuse tomorrow, although i've taken it off & it doesn't appear to have blown - unless the actual fuse bit isn't visible

+1 ^
Re limp mode... did you replace the MAF with a quality version or cheapo?

i bought it from a Mercedes dealership & they fitted it.

 

[jph77]

Where's the EGR valve and how do I clean it?

 

[jay1983]

Egr valve is on the right hand side of the engine (as you look at it from the front). You will need to remove the engine covers to get to it. It has a large black pipe attached to it. The egr valve is held onto the intake manifold with 3 torx screws.



(the silver part on the left of pic)

 

[Jane270ML]

Egr valve is on the right hand side of the engine (as you look at it from the front). You will need to remove the engine covers to get to it. It has a large black pipe attached to it. The egr valve is held onto the intake manifold with 3 torx screws.

View attachment 31018

(the silver part on the left of pic)

One of the screws is a real PITA to get to, you may have to remove other bits to access it.
Don't try to pull the boost pipe from the EGR without first removing the large spring clip otherwise you'll damage the locating lugs & may end up with an air leak.

 

[Jane270ML]

This link will give you some idea of what's involved...
http://www.mbclub.co.uk/forums/engine/105515-ml-w163-270-egr-pipes-manifold-cleaning.html

... do a further search on the forum for egr - you'll be surprised what you unearth.

 

[mexican gaz]

Hi think you will find fault is with the inlet port shut of motor, blows the fuse in the back part of front fuse box.

 

[jph77]

Hi think you will find fault is with the inlet port shut of motor, blows the fuse in the back part of front fuse box.

Ok thanks. Where's the fuse box?

 

[panason1c]

Ok thanks. Where's the fuse box?

Dont you have a handbook for your vehicle?

 

[jph77]

Dont you have a handbook for your vehicle?

Sorry Dad! I'll look in the handbook when I get home from work then drive twice the distance to buy a fuse!

 

[panason1c]

Sorry Dad! I'll look in the handbook when I get home from work then drive twice the distance to buy a fuse!

Hey son, you forgot to ask how to open the bonnet!...

 

[jph77]

Hey son, you forgot to ask how to open the bonnet!...

behave, if i knew what i was on with i wouldn't be asking for help would i?

 

[panason1c]

For the future benefit of the more appreciative posters who need help on this subject, here is a diagram showing the location of the fuse for the engine fan/heated seats.
......fuse..#21 and you will also need the plastic nut...#11 (only tighten the nut lightly or it will break)

 

[jph77]

Thanks for your help.
Out of interest, why is the red nut plastic? I broke the new one but put the old one back on, I assume this don't affect the function of the fuse?

 

[fozzy3k]

For the future benefit of the more appreciative posters who need help on this subject, here is a diagram showing the location of the fuse for the engine fan/heated seats.
......fuse..#21 and you will also need the plastic nut...#11 (only tighten the nut lightly or it will break)

Sorted thank u pick up ml today with this problem I try this tomorrow