[Keithlan1978]

I need a bit of help, I bought a 335d 2 weeks ago which wasn't getting upto temp an was only hitting 65-75

It would go upto over 90 if idling but as soon as I started driving it would come right back down

I've since put 2 new main thermostats on it (not from bmw) and was no different and if anything was a bit worse as it was only running about 55-60 so today I've replaced it with a genuine one from bmw and it's still not getting upto temp and only hitting 65-75, if it hits 75 with a bit of sitting in traffic it will come back down to 65 ish when driving again

The EGR cooler has been removed and previously mapped out before I bought it along with the dpf and swirl flaps so I know it can't be the thermostat on the EGR cooler

Only codes when scanned are for glow plugs and auxiliary water pump

Anyone got any ideas what it could be? Thanks

[MrSweet1991]

Personally I would have bought both from BMW, the main and EGR stats open and close at different temps. One will hover you around 70's and the other will hover low 80's so your definitely in the faulty thermostat temp range. Furthermore, you did say once you replaced your stat with BMW that your temps went from hovering 55/60 to 65/70 so it did seem to make a difference.

If it's hovering in the 70's have you only replaced one thermostat? If you have then remove the EGR thermostat and see if you can blow through it, if you can that's a sure sign it's stuck open.

[rasa bmw]

ALWAYS DEALER FOR STATS OR SENSORS...they aint much dearer any how,,both stats for under £90

[Daviebrown]

Ok just so i read your post correctly i’ll clarify, you replaced the main thermostat with a non bmw stat on 2 occasions? You did NOT replace the egr thermostat because the cooler has been removed and mapped out?
I agree 100% that the main stat should only be replaced with a bmw dealer part, i have learnt this the hard way. I have had a brand new generic one fail at first start up and this sent me down the path that you are now on. Given the information that you have supplied i think you should check the removal of the egr cooler to see that whoever removed it DID NOT simply join the two hoses together. This is an easy rookie mistake as the hoses need to be plugged not joined. If everything is in order then my next step would be a dealer thermostat.

[Tambohamilton]

So you've got a genuine BMW main thermostat in - that's sorted. Sounds 100% like whoever removed the egr cooler simply joined the hoses - this will give exactly the symptoms you describe.

Really grinds my gears how some people don't understand how these things work, so they 'delete' (so pretentious; it's not very clever just to take parts off your car and turn off stuff via software!) them, and pretend it's fixed. As if these things weren't fitted for a reason; somehow the car/world will be better off without them!? Anyhow, rant over.

[MrSweet1991]

Originally Posted by Tambohamilton

So you've got a genuine BMW main thermostat in - that's sorted. Sounds 100% like whoever removed the egr cooler simply joined the hoses - this will give exactly the symptoms you describe.

Really grinds my gears how some people don't understand how these things work, so they 'delete' (so pretentious; it's not very clever just to take parts off your car and turn off stuff via software!) them, and pretend it's fixed. As if these things weren't fitted for a reason; somehow the car/world will be better off without them!? Anyhow, rant over.

Lmao, I have no idea how I missed the section of him deleting the EGR. That said, if the EGR was deleted as in physically removed then the coolant hole gets threaded and plugged from what I've read so those symptoms shouldn't happen because in theory it would be permanently closed whereas a faulty EGR stat would stay open preventing the temp increasing?

[Tambohamilton]

I bet a cup of tea at my place that the issue is something to do with the egr removal, and how the coolant lines have been dealt with.

OP, can you post a picture of the egr cooler area of your engine, so we can see what's going on?

[Chappers 71]

Op, why would you buy a car that's had a dpf removal

[Keithlan1978]

Originally Posted by Chappers 71

Op, why would you buy a car that's had a dpf removal

Why not???

[Keithlan1978]

Guys thanks for your comments, I've now found the problem, whoever done the egr delete joined the hose that goes to the main thermostat instead of blanking it so had a constant feed of water like in the picture

[Daviebrown]

Just as i thought, just cut it through the middle and put a bung and jubilee clip on either end. If you can clamp it in the meantime and take it for a drive i think you will see the temp up to high 80’s at least.

[nick46]

Originally Posted by Keithlan1978

Why not???

Because its an mot failure. Also if you get caught without it - for example after you've had an accident when it is inspected by the insurance company, your insurance will be null and void and you will not be getting a penny. Finally its pointless to remove it, there just isn't the need to.

[Keithlan1978]

Originally Posted by nick46

Because its an mot failure. Also if you get caught without it - for example after you've had an accident when it is inspected by the insurance company, your insurance will be null and void and you will not be getting a penny. Finally its pointless to remove it, there just isn't the need to.

Thanks for your words of wisdom

[Keithlan1978]

Originally Posted by Daviebrown

Just as i thought, just cut it through the middle and put a bung and jubilee clip on either end. If you can clamp it in the meantime and take it for a drive i think you will see the temp up to high 80’s at least.

Thanks mate that's exactly what I'm going to do, since I've clamped it temporarily it's been perfect getting upto 88-92

[Daviebrown]

Its good to hear a reply, quite often when giving advice there is no feedback to say if suggestions were successfull

[Keithlan1978]

Originally Posted by Daviebrown

Its good to hear a reply, quite often when giving advice there is no feedback to say if suggestions were successfull

Totally agree, Always good to reply incase anyone in the future has the same issues mate

[Tambohamilton]

Originally Posted by nick46

Because its an mot failure. Also if you get caught without it - for example after you've had an accident when it is inspected by the insurance company, your insurance will be null and void and you will not be getting a penny. Finally its pointless to remove it, there just isn't the need to.

Not meaning to jump in with the bashing... Removed dpf is also an indicator that anything upstream of it might not be working well (leaky/clogged injectors, boost leaks, bad turbos, etc) and causing excess soot...the easy 'fix' for which is to remove the dpf... To me it's a huge red flag (as well as not road legal, etc).

Good luck with the car!

[bugra101]

Out of interest, I replaced both my thermostats with Behr/Mahle brands. Are they the ones that people have had issues with ?

Thanks!

[Keithlan1978]

Originally Posted by Tambohamilton

Not meaning to jump in with the bashing... Removed dpf is also an indicator that anything upstream of it might not be working well (leaky/clogged injectors, boost leaks, bad turbos, etc) and causing excess soot...the easy 'fix' for which is to remove the dpf... To me it's a huge red flag (as well as not road legal, etc).

Good luck with the car!

Every diesel car I've had I've removed the dpf on and not cos there was any problems but simply cos I don't like them or the egr valves, everyone's different and I understand what people are saying but it's my car an my choice mate

[Keithlan1978]

Originally Posted by bugra101

Out of interest, I replaced both my thermostats with Behr/Mahle brands. Are they the ones that people have had issues with ?

Thanks!

I'm not sure mate, mine was still the original from factory and I replaced it twice with one just from an auto parts place and it still never got up to temp so I then bought a genuine one from bmw and that still never got upto temp so I started looking into how the egr had been removed and whichever idiot done it hadn't blanked the pipe going to the main thermostat and that was my problem

I'm talking about the main thermostat as mine doesn't have the egr one on anymore but at least now it's got a genuine one from bmw on and when I compared the genuine one next to the independent one I wouldn't of fancied leaving the independent one on

[bugra101]

Originally Posted by Keithlan1978

I'm not sure mate, mine was still the original from factory and I replaced it twice with one just from an auto parts place and it still never got up to temp so I then bought a genuine one from bmw and that still never got upto temp so I started looking into how the egr had been removed and whichever idiot done it hadn't blanked the pipe going to the main thermostat and that was my problem

I'm talking about the main thermostat as mine doesn't have the egr one on anymore but at least now it's got a genuine one from bmw on and when I compared the genuine one next to the independent one I wouldn't of fancied leaving the independent one on

I see, EGR thermostat that I took off had both BMW and BEHR logos on it. But main thermostat only had BMW logo and looked identical to the BEHR one I put in.

My EGR is also mapped out only, it isn't blanked. Has anyone had issues with mapping out only but not blanking?

[Keithlan1978]

Originally Posted by bugra101

I see, EGR thermostat that I took off had both BMW and BEHR logos on it. But main thermostat only had BMW logo and looked identical to the BEHR one I put in.

My EGR is also mapped out only, it isn't blanked. Has anyone had issues with mapping out only but not blanking?

Should be ok then mate, the main one I'd definitely want a genuine bmw one on cos they're a pain in the ass to get at so definitely only want to be doing it once

The egr as long as it was functioning properly or closed when it was mapped out then it should be fine, if it was stuck open then no that wouldn't be fine

People blank them off as they can cause catastrophic damage if they fail so if it was me then even if u don't want to remove it (which is fine) I'd definitely consider blanking it for the sake of a few ££