[Shindog32]

I have a 2006 325i with 76,000 miles on it. I have never had any issues with this car, Ive changed the oil and filters regularly and have only had to install brakes and a new battery since I purchased it 4 years ago with 38,000 on it. It did have the tapping noise recall done under waranty witch I belive was change out the lifters. other than that no problems untill yesterday.
I was driving from Houston to Dallas on a fairly busy roadway averaging about 80mph and about 81deg. outside (fairly cool for TX). About half way (2 hours on the road) the car over heated and went in to limp mode. I babied it to the next exit (about 10 miles) and let it cool. There was coolant all over the passenger side of car and fans were running full blast. Car cooled down and while waiting on tow truck (2hours out) I decided to add coolant and check for a leak. Contary to what the BMW shop had told me the car did not stay in the limp mode and ran fine. I drove it about 15 miles and checked for leaks/issues and all was fine except for the check engine light. So I drove the rest of the wasy to Dallas and got the codes read.
The car runs rough at idle and has the following codes:
P171, P0174 P1445. I was hoping to find out if anyone knows what could have happened here? No sign of a leak anymore so could the coolant have just been low and caused the overheat? Honestly when the extended warranty expired about 1.5 years ago I have NOT checked the coolant. I just figured its something that doesnt just evaporate so I never checked it.
Any thoughts or suggestions would be greatly appreciated.

[longnvu]

Water pump going out

[mir-ali604]

It most likely your waterpump. Same thing happened to me last week. Get it the waterpump and thermostat replaced asap or you may end up with way more engine damage.

[777ER]

P0171 - Fuel System Too Lean (Bank 1 or 2)
P0174 - Fuel System Too Lean (Bank 2)
P1445 - Diagnostic Module Tank Leakage Pump Control Circuit Signal Low

None of these seems to be related to the cooling system failure.

The fans are running high speed due to the engine block temp but there's no coolant flowing inside the cooling system. Cooling pump is bad...feel the radiator and the upper coolant hose on the driver's side from the engine to the radiator...it will feel cool to the touch so this is a good way to know it's not pumping coolant as it should.

If you were low on coolant, you would've gotten an warning that the coolant level is low.


Mine went out about 76-77k....the cooling pump went bad and stopped working...costed $1,500 to replace the cooling pump and t-stat.

[Efthreeoh]

Water pump. Replace the water pump and thermostat at a BMW Independent repair shop for $800. Water pump failure does not throw a OBD II (SES light) code. A failed heater circuit in the t-stat will, but that failure doesn't cause over heating, just an emissions-related failure OBDII code.

[Shindog32]

Well, I drove 4 hours back to Houston last night and no issues and the check engine light went out. But I guess its possible the pump is going out even though it started working again. I have to go to San Antonio in 2 weeks so I guess I had better just replace it to be on the safe side. I really appreciate the help from all you guys! Im not sure there is a DIY for the pump and thermo replace so I guess Ill bite the bullet and go have it done. Thanks again you guys! Still has a rough idle but maybe that will go away after I replace the pump and clear the codes? Fingers crossed it didnt cause a seperate issue!

[Shindog32]

Originally Posted by 777ER

P0171 - Fuel System Too Lean (Bank 1 or 2)
P0174 - Fuel System Too Lean (Bank 2)
P1445 - Diagnostic Module Tank Leakage Pump Control Circuit Signal Low

None of these seems to be related to the cooling system failure.

The fans are running high speed due to the engine block temp but there's no coolant flowing inside the cooling system. Cooling pump is bad...feel the radiator and the upper coolant hose on the driver's side from the engine to the radiator...it will feel cool to the touch so this is a good way to know it's not pumping coolant as it should.

If you were low on coolant, you would've gotten an warning that the coolant level is low.


Mine went out about 76-77k....the cooling pump went bad and stopped working...costed $1,500 to replace the cooling pump and t-stat.

OUCH! Hope I can find a better deal... that is steep!

[mike-y]

get it done asap. intermittent failure is the first step. although it has started working again, it WILL eventually fail permanently.

And if it does do it again, don't drive it if the red warning light is on, you risk damaging the engine.

[techwhiz]

My friend recently had an intermittent failure on a 2006 5-series.
Did not immediately take it to the shop to get it fixed.
Needless to say, when it died it was a bad location and the car had to be driven.

$7200 mistake.
Now needs a new engine.

[Efthreeoh]

Originally Posted by Shindog32

Well, I drove 4 hours back to Houston last night and no issues and the check engine light went out. But I guess its possible the pump is going out even though it started working again. I have to go to San Antonio in 2 weeks so I guess I had better just replace it to be on the safe side. I really appreciate the help from all you guys! Im not sure there is a DIY for the pump and thermo replace so I guess Ill bite the bullet and go have it done. Thanks again you guys! Still has a rough idle but maybe that will go away after I replace the pump and clear the codes? Fingers crossed it didnt cause a seperate issue!

There are DIYs for both the 325i/328i (N52) and the 335i (N54/N55) in the DIY section. The whole water pump issue is well discussed in the maintenance section. Overheating in-line 6's (with the long cylinder head) is never a good idea.

[Shindog32]

I guess i better have a compression test done. I drove it about 5 miles with the light on! I know... not smart but the hwy was packed and shoulder was very small. Anyway im sure the inconsistant RPMS at idle must be a seperate issue. Those codes that dont seem to have anything to do with the overheating worry me! They could be the result of a leaking head gasket. I did look at the oil and no choclate milk but i guess the leak could be into the combustion chamber and not the crankcase and that would most likely throw some codes. Thanks for the tip on the DIY, i looked in the DIY section but not in maintenance. Ill search it now.

[Shindog32]

Well, Im waht they call "work in progress" I guess! Found out today the rough idle (inconsistant RPM'S) was indeed a seperate issue. I had removed the oil cap and since this car just turned 76000 and is a weekend driver at best I have always taken it to a local Beemer shop for oil changes. It seems as the hissing sound (vacume leak) from the oil cap was causing the rough idle because when I removed the oil cap I took the retaining ring with it and did not notice that it must snap onto the valve cover before you try to tighten the cap! Yes im a rookie! Now that thats behind me Im waiting on my parts to replace the EWP.

[MalcolmV8]

As others have stated sounds like your water pump. Mine did the same thing where the cooling fans where going full blast but since the coolant is not circulating the car can't cool. I did that trick with the button on the dash where you can get to your coolant temp and saw how hot it was (googled the procedure on my phone). Had to call a tow truck and get towed home.
I found a DIY online and did the pump and thermostat myself. It's pretty cramped in there but can be done at home.
I'd replace it before you get stranded and need a tow or worse damage your engine.

[DUI Elite]

Mine overheated once and I immediately replaced water pump and thermostat.

It requires a BMW Technic tool or scanned at BMW to see the fault codes for the thermostat.

It's the closest thing to a sign that the water pump will be going out soon with these Electric water pumps.