Friday, September 23, 2011

Is it hard to change the thermostat on a 5 series BMW?

Also, if it's running hot, isn't this the first thing to try? What else might be the problem? Thanks.
Is it hard to change the thermostat on a 5 series BMW?
It is entirely dependant on the year and engine as to the difficulty of the T-stat change out.

Well the first thing I would do is check your coolant level. Sorry,I am not meaning to be a wise guy by saying that but I have learned on this board to not forsake of take steps for granted.

After that make sure it holds coolant.

Check for obstructions froward of radiator.

Confirm electric fan operates and goes up to speed

If not electric the fan clutch should stop the blade from being turned by hand immediately when vehicle off

Start and warm up.

Note flow going into pressurized recovery chamber.

while running, with glove, squeeze upper radiator hose slightly. You should be able to recognise flow activity inside it.

confirm that air is bled out of system.

BMW's typically use a finer resolution core to allow more radiator cooling capacity. The flip side to this is that they may clogg easier, especially along the bottom of the radiator. If there is a large amount of coolant going into the pressure recovery chamber via a 5/8 bypass hose there is a chance their could be a restriction in the radiator cores.

There is really no sense in flushing the unit on the vehicle. better to give it a good backflushing and look in the bottom with an inspection mirror. If there is still lots of sediment then take it to a radiator shop.

Check to see in coolant has been escaping via the weep hole of the water pump. If so then chances are the the pump is bad. Confirm that the drive belt is within spec of the driven water pump pully, and nothing slick has wound up on it.

Look at the hoses, as they will usually show evident marks where it is leaking.

Only at this point would I consider the T-stat. That is, if all other above has passed.

Not a part that sticks as often as one might think, unless additives were put in the system such as allumafil or stop leaks.

One thing about BMW's is that they are not very shy about coolant problems. They are usually %26quot;in your face%26quot; problems that can be seen

The newer BMW's are equipped with abs couplings that break quite readily. The parts department at BMW has an abundant supply of these and will love to sell you a couple.



With you

haha get it? As if you didn't already know.

That's about the best general guidance I can give on a 5 series without a year or engine.
Is it hard to change the thermostat on a 5 series BMW?
most cars easy and cheap to do just follow top radiator hose back to top of motor remove hose and two bolts in housing and lift housing off scrape off old gasket replace new gasket and new thermostat about same on all cars some easy some not so much but al some what easy job here a few lick might help you do it but its easy might cost you 30 bucks thermostat like 15 gasket 10 and a jug of coolant
Changing the thermostat is not rocket science. But before doing so

check and be sure that the cooling system has no air bubbles inside, that the coolant level is OK, that there are no leaks and that the water pump is working normally. Spending money on unnecessary repairs sucks.

To replace:

a) Detach fan blade from water pump (you need special tools)

b) Remove radiator fan shroud along with the fan blade from the front of the engine (if you want to make your removal of the thermostat more convenient to do)

c) Detach the two hoses connected to the thermostat (remember to catch the coolant that drains out below).

d) Detach the cable/wires connected to the thermostat

e) Loosen the engine lifting hook at the left front side of the engine since it would block removal of the thermostat

f) Remove and replace thermostat

g) Re-install removed parts, add coolant and perform bleeding proper bleeding procedure to remove air inside cooling system.

Welcome to the DIY club!
Year buddy year. The 5 series goes all the way back to the 70's.
My BMW did this same thing. It would -always- run at 3/4 if not 7/8 the temperature gauge... and stay there. I ran heavy oil in it 10W_40 or 20W-50 always to help, and it was cool because the engine used as little fuel as possible. No reason or anything for this, it also did this after i flushed my radiator myself. Then one day it just made the jump to ovrheat with my best friend at the time in the car. It blew a hose from pressure. She was stronger than i was, so she put the hose back on. Car drove fine, had blown head gasket and i sealed it and it ran fine again.

There is a bellhousing with the thermostat.

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