No Cabin Heat

I was wondering if there was a sure way to rule out bad water pump/ t-stat?

Symptoms. No cabin heat and car runs hot.

Even that I'm new here but I can help:
had the same issue with my car when I got it 2 weeks ago.
Coolant pipe is leaking 199% and your electric water pump is done. I saw 3 different shops and none of them could find the real problem.
Replaced water pump and tstat- got nothing!
If you replace the electric pump you will get heat but the real problem is in the coolant pipe. Spent a 1000$ to fix it and lots of time.
Normal temp is 105C if it's higher you have a problem.

Did you have any coolant leaks while you were trying to get the problem diagnosed? Did a lot of pressure build up in your reservoir? I wanted to try a little more troubleshooting before going after the pipe. When did you finally know for certain that it was PIPE?

Originally Posted by dablk1

Did you have any coolant leaks while you were trying to get the problem diagnosed? Did a lot of pressure build up in your reservoir? I wanted to try a little more troubleshooting before going after the pipe. When did you finally know for certain that it was PIPE?

The funniest thing wheep hole was dry, but when they removed my water pump (it's 2009 almost new) my mechanic put his finger and inspected the gasket and found that lower part was torn and therefore water was getting back into valley pan instead of going into to the block, therefore not enough flow from water pump!! In other words wheep hole is not only about loosing coolant, it's the way to kill your engine.
Easy test:
When car is cold remove the coolant cap and watch for a small return hose it should be peeing really good not like with prostate cancer)) lol
Mine was very weak, barely peeing, after coolant pipe it's peeing like 10 yrs old boy again
But your electric pump is dead, don't drive like this! You'll kill your engine. If you want just heat replace the electric pump, but it's not a solution

Let me make sure I understand. The car has been sitting for 3 days. It's nice and cold. So I should remove the coolant cap and water should be peeing from the small hose that runs across the top of the radiator to the reservoir?? if not, then what...does that mean the pipe is leaking?

Originally Posted by dablk1

Let me make sure I understand. The car has been sitting for 3 days. It's nice and cold. So I should remove the coolant cap and water should be peeing from the small hose that runs across the top of the radiator to the reservoir?? if not, then what...does that mean the pipe is leaking?

You're correct. Start the engine, open cap and watch. Well BMW manual says coolant system is self bleeding, so if after venting procedure heater is still cold it means you have a major leak. Well this all makes sense if your water pump is good. What year is your water pump and how may miles?

Well I fixed all of the leaks. The hose pees like no ones business. I'm uncertain about the year of the water pump and such. I have a 2002 with 102k on the clock.

Originally Posted by dablk1

Well I fixed all of the leaks. The hose pees like no ones business. I'm uncertain about the year of the water pump and such. I have a 2002 with 102k on the clock.

This is how it started in my case:
No heat, but if you rev the engine it will get hot:
Diagnostics showed broken electric pump, replaced it, got heat, but the car was running hot.
Then:

Ok, mechanic noticed that lower radiator hose was always cold like tstat was stuck closed, he tried to bleed the system lots of times- no result.
If everything is ok with cooling system, your lower hose should get hot when car is ~105C and aux fan kick in, if it does not happen it means you have air in the system or leak.
Mine was always cold even the car was 110!
Now everything works great 103-105 working temp and then the aux fan kicks in.

Well initially my heat was fine. I can't recall exactly when, but then it stopped working while I was trying to track down my coolant leaks. I'm really leaning towards the tstat because it feels like there is water in the heater hoses but it's just not getting hot.

I installed a new tstat. Still no heat and the lower radiator hose remains cold/cool to the touch. I am not losing one single drop of coolant.

Originally Posted by dablk1

I installed a new tstat. Still no heat and the lower radiator hose remains cold/cool to the touch. I am not losing one single drop of coolant.

I also wasn't loosing any coolant.

Ppl are strange why are you repeating my mistakes??
I told you, we replaced tstat, then water pump, then my Indy said WTF? he tested cooling pressure and it dropped which was indication of the leak. Coolant pipe is not only about loosing coolant it's about air in the system and poor circulation.
Btw check your electric pump located on driver side front rail near headlight. It's 99% dead bc even with air in the system it will help with heat in the cabin. Set blower on 90f and touch the pump it should be vibrating.
Did you try venting you system? Just set heater on high blower on low and with cold car run the engine on idle for 2-3 mins. If it doesn't help you have 100% my problem
Btw when we removed the valley pan my Indy found it was leaking on the back of the block bc 2 bolts were rusted.

Well it appeared that there was good "peeing pressure" inside of the reservoir which I thought ruled out the waterpump and cooling pipe. You stated that you pressure wasn't good here. When you say electric pump are you referring to the auxiliary water pump?
I guess my biggest problem is trying to solve the over heating issue/ cabin heat is secondary.

This is what happens now. 1) I fill the car with coolant. 2)in roughly 5-10 min upper radiator hose is nice and warm. 3) I.retold temp is set to 90, no cabin heat after an additional 5 mins. 4) excessive pressure in the reservoir(I crack the cap and it's boiling). 5) I shut the car down to avoid overheating.

I'll be tackling the "coolant pipe" issue on my own if that is the case. I just wanted to be certain to rule out everything else, before I really had to dig in.

If the t-stat was faulty it would throw a code. I would look at bleeding the cooling system of any possible air in the system (air lock) If there is no air present look at that water pump. If there is air start looking for a leak. Keep us informed.

I am 100% percent sure that there aren't any leaks right now. I'll try to bleed the system. Will keep the forum updated.

Originally Posted by dablk1

I am 100% percent sure that there aren't any leaks right now. I'll try to bleed the system. Will keep the forum updated.

Replace aux pump, it will help with venting procedure. It's easy one 10mm nut holding it

Will do, but won't be able to get another until Monday.

Well here's the update. I replaced the coolant pipe. The car ran fine for a day and a half. I am now back to squae one. I am having the same problem all over again. I am going to dig in again tonight. Will keep you guys updated.

Can you give us an update? It's been quite some time, did you just sell it? lol.. I am having similar issues.. my lower hose is heating just fine.. and I have good pressure on the vent hose pouring into the coolant, but I am still running a little hot at idle..

I got rid of it.