no real heat

Post Fri Feb 20, 2015 5:19 pm

It all started like this....

http://www.e30zone.net/modules.php?name ... c&t=259110

Now I have linked the two pipes together after the old motor and pump were taken out , and had very little change.
Lets get this straight, the pipe from the back of the head goes to the top of the heater and the other goes to the bottom??
If so then the top hose was hot and the lower was not.

Help please !!

Mart.

Post Fri Feb 20, 2015 5:26 pm

The pipe from back of the head goes to the bottom heater pipe.

Post Fri Feb 20, 2015 5:36 pm

jmc330i wrote:The pipe from back of the head goes to the bottom heater pipe.

I will check right now .

Mart.

Post Fri Feb 20, 2015 5:46 pm

Well mine dose not , it goes to the top. !!

When somebody changed it from injection to a webber do you think they got it wrong?
The two pipes are in really good shape as in the last two to three years old.

Mart.

Post Fri Feb 20, 2015 6:17 pm

Just realised this is an M10 and I've not worked on these, but I can't see it being different from other BMW engines.

If work has been done that involves those pipes, it's entirely possible they have been refitted the wrong way around. This results in little to no heat from the heater (especially at revs higher than idle) and usually a 'thudding' noise from the heater valve at higher revs as water is being forced the wrong way through the valve.

Post Fri Feb 20, 2015 6:23 pm

They are often refitted the wrong way around, because that's the way they look like they should be - not crossed over.
The pipe from the back of the head goes to the bottom stub on the bulkhead on all BMWs.

Post Sat Feb 21, 2015 11:19 am

Thanks guys. lets hope this is the problem.

Mart.

Post Tue Feb 24, 2015 5:14 pm

Well that didn't work either.
I ran her up to temperature for a good 30 mins and no heat from the heater.

Any ideas please?

Mart.

Post Tue Feb 24, 2015 6:26 pm

Pipes off again, and connect a garden hose to the bottom stub pipe, to check that water will flow through the matrix freely. There's an electric valve on the side of the heater box that can be forced shut if water is flowing the wrong way, and may have stuck.
When you refit the heater hoses, you should do so with coolant flowing from the pipes, so that no air is trapped.

Post Wed Feb 25, 2015 8:41 pm

Do you have a fuse number and location for the electric valve please?

Mart.

Post Wed Feb 25, 2015 8:57 pm

The valve is to the right of the glove box. To get to it you will need to take out the center console, the glove box and two pieces of trim. I found it worth taking the passenger seat out to make access easier.

Post Wed Feb 25, 2015 10:23 pm

The electric valve is protected by the only conventional fuse on an E30 that isn't in the fusebox. The fuse is in an inline fuse holder in the wire to the valve, BUT the valve is open when no power is applied. Applying power to it closes the valve.

Post Sat Feb 28, 2015 2:26 pm

OK so what is the purpose of the valve and if no power /blown fuse would it allow the flow of coolant ?

Mart.

Post Sat Feb 28, 2015 2:31 pm

The purpose of the valve is simply to completely cut off the warmth from the heater when the temperature knob is set to fully cold. As soon as the knob is moved a few degrees, power to the valve is removed.
With no power, the valve should allow the full flow of coolant.

Post Sat Feb 28, 2015 2:53 pm

Cheers Brian, are they readily available ?

Mart.