M52 (pre-98) crank sensor replacement....

[Maxxxer]

Just a quick one - can anyone point me in the direction of a How-To or advise how hard this is to do?

As mine is an early 2.8 M52 the crank sensor is front left of the car (rather than back right under the starter motor) and the only advice on Pelican parts is to where it is located, and not much else.

I'd like to have a crack at replacing it myself (already had a quote for the part from Soper's) so if anyone can advise having done it themselves or point me in the right direction I would be eternally grateful...!!


**Edited to add, I am getting a 53 crankshaft sensor error on my ODB Reader and the symptoms point to this being the case **

 

[Jjim]

@Grumps did you change yours?

 

[t-tony]

I did the one on my 2.0 Z3 and it was above the Starter motor. Can you post a picture of the location please?

Tony.

 

[Maxxxer]

Location is as per the diagram below (number 9) (at work currently, so i cant actually get to the car!);

I recall seeing a thread whre @Davyhoogy had the same issue - his was/is in the same place (in later cars its under the starter motor - pre-June '98 its in the location above.....)

 

[Jack Ratt]

I took mine out when I rebuilt the head on my car last year. It's only held in with one bolt and the plug goes into the loom. I put my old one back in when I reassembled everything. Nothing springs to mind that caused me a problem, but I removed the radiator and cooling fan during the rebuild so I had plenty of room to work.
I removed the anxcillary belts and alternator belts too for my job.
You'll need a 32mm open ended spanner to get the fan off but everything else is pretty straight forward.
While you've got the front end stripped you may as well it freshen up if you need to, ie, new belts, tensioner pulley's, water pump and thermostat etc

 

[Grumps]

@Grumps did you change yours?

Yes mate. Pin connector is on the right front near the top of the engine under the inlet manifold, the sensor is half way down the engine casing on the right. Not hard to change just fiddly getting the pin connector in.

 

[Grumps]

I can pop round and give you a hand when your ready.

 

[Maxxxer]

@Grumps Is the sensor on the right or the left of the engine?
I thought it was on the left lower down (as you look at it from the front of the car), with the connector under the inlet manifold on the right?

If I'm wrong then fair enough - I may have tried to clean the wrong sensor at the weekend..!

 

[Jack Ratt]

The crank sensor is on the front of the M52 engine, in the centre and directly above the crankshaft pulley.

 

[Maxxxer]

Does it of look like this by any chance (Orange arrow-stolen from Pelican Parts guide on a 3 Series E36)? I did give this a clean just in case that might have helped (nope!).

Also, can I just check before i spend £117 on a sensor - the car starts (albeit with a splutter) then idles roughly until warm. There is a slight loss in power. I have done a error code read and I do have 53 crank sensor, although I have heard it might not start at all if its the crank sensor, and could instead be the cam sensor (as the car does eventually start...)

I figured it's crank sensor as that's the error I'm getting and the symptoms do seem to match others on here who have replaced the same thing, but I just want to make sure since its another £100 quid for the next sensor (plus garage time, given I seem to be struggling to even locate it let alone swap it!)

Sorry if I'm asking stupid questions; previously my weekend car was a 1975 Midget - much simpler to diagnose and work on..!

 

[Lee]

Hi Maxxer have you check your Vin against RealOEM ? With all the Zeds ive worked on I've never seen one up front on the crank like this.

I've only come across this style on E36's mostly the earlier M52's 2.5L etc.

If it is that design It's actually easier than the other type. Remove the Fan and shroud along with that plastc cover and feed the sensor through, It's plugged in under the manifold.

 

[Maxxxer]

Hi @Lee I've checked the VIN against RealOEM, and Sopers sent the diagram posted up there ^^^^ so i knew what i was looking at. It's a Feb 1998 model, so its the early 2.8 (rather than the later (June 98 onwards I think) which has it beneath the starter motor - I've checked there and all I have is a blanking plate). I'm happy to give it a go if that's where its located and its relatively easy.

Do you think the symptoms (and error code) point to this rather than the camshaft sensor?

 

[Lee]

Hi @Lee I've checked the VIN against RealOEM, and Sopers sent the diagram posted up there ^^^^ so i knew what i was looking at. It's a Feb 1998 model, so its the early 2.8 (rather than the later (June 98 onwards I think) which has it beneath the starter motor - I've checked there and all I have is a blanking plate). I'm happy to give it a go if that's where its located and its relatively easy.

Do you think the symptoms (and error code) point to this rather than the camshaft sensor?

Cool, that's a good one to remember. With the M52's cutting out and stalling is normally related to Crankshaft sensor, and missfires and hesitant running/overfueling the Camshaft.

Whats your symptoms I couldnt see it above ?

 

[Maxxxer]

@Lee

Also, can I just check before i spend £117 on a sensor - the car starts (albeit with a splutter) then idles roughly until warm. There is a slight loss in power. I have done a error code read and I do have 53 crank sensor, although I have heard it might not start at all if its the crank sensor, and could instead be the cam sensor (as the car does eventually start...)

 

[Lee]

@Lee

Yes it's possible but do one more thing for me. Unplug the maf and see if it keeps doing it.

Clear the code go for a drive and see if it comes back. Had simular issues with a MAF.

 

[Maxxxer]

OK I'll give it a go next chance i get - I did try unplugging the MAF whilst it was running to see if it cleared up the rough idle (it didn't) and the next thing i did was read the codes (already had the MAF off to replace the rubber hose behind it in the hope it might be a cheap fix!).

At that point I got MAF, crank and camshaft error codes - I cleared these, restarted the engine and let it idle, then re-read the codes.

That's when the only code that came up was 53 crankshaft error.

 

[Jack Ratt]

Yes, @Maxxxer , @Lee that is the correct sensor for a pre facelift M52 2.8. single vanos engine. Both of my Zeds are identical to that photo.
I can't comment on the symptoms as I removed and refitted mine during an engine rebuild, and my sensor was not faulty.

 

[Grumps]

@Grumps Is the sensor on the right or the left of the engine?
I thought it was on the left lower down (as you look at it from the front of the car), with the connector under the inlet manifold on the right?

If I'm wrong then fair enough - I may have tried to clean the wrong sensor at the weekend..!

On the right as you look from the front mate. About half way down.

 

[Maxxxer]

Right then peeps - part ordered and now delivered, so my (hopefully) last question is this;

I can see where the connector end plugs in - is there an easier way to get to it without removing the inlet manifold?

It's going to be fiddly, but if i can get to it relatively easily (somehow) I'll tackle it myself...

 

[Maxxxer]

Just a quick update to this - part arrived, i had a go and to be honest it was a right royal PITA.

For reference;
- You can get access to the sensor from underneath on Axle stands
- You can get access to the plug (just) if you put your hand under the inlet manifold (although it does help to take off the airbox)
- You can remove the radiator fan shroud, although you will have to drain the coolant (so i didn't bother and refitted it).
- You can remove the cable guard without removing anything else with a long screwdriver

Alas, I could not get the old sensor out for love nor money. So I booked it in at my local garage, and it took them an hour to remove and refit the new one. The invoice even states the old one was stuck fast and was difficult to remove..!

£54 all in, and the car now starts and runs lovely....