Quick Answer Please - Heater Not blowing hot.. Headgasket??

Mon Apr 20, 2009 12:34 am

I'm going to buy a 325 tomorrow. Everything is fine but when I test drove it, the heater didn't blow hot air. The guy said it's probably just blocked.

I'm just a bit worried as my friend has mentioned that if it doesn't blow hot air from the heaters, it is a sign of head gasket issues?

Is this true?

What are the symptoms?

Mon Apr 20, 2009 12:57 am

It's probably the head gasket.

There is a heater matrix inside the dash of an E30. This matrix acts as a heat exchanger between the hot water from the engine and the air which is blown over/through it by the blower fan. Like your engine's radiator operating in reverse.

So the hot water which circulates through the engine also goes through this heater matrix for the hot air system.

The knob that controls the ambient temperature inside the car regulates how much of that hot water from the engine comes through the matrix.

If the heater is not blowing hot it means that there is for some reason no hot water from the engine coming into the matrix.

There are 3 main possible reasons for this:

1: The headgasket is gone in the engine, therefore the hot water is not circulating round the engine as it should be. This is caused by gas from the combustion chambers/cylinders being present in the water system. This is because the head gasket has failed and allowed this to happen.

2: The heater matrix developed a leak and was disconnected to stop it. This is uncommon because it's a pretty ignorant way of solving the problem.... but not unheard of !

3: The knob which controls the temperature inside the car is broken..... Double check this !

If the head gasket is gone there are a couple of main symptoms:

1: After the car has been driven or warmed up. Squeeze the water pipes going to the radiator from the engine These will probably be rock hard. Also if you loosen off the cap on the water header tank slightly it'll tremble like a volcano waiting to errupt and hot water will gush out under presure.

2: There may be a mayonaisey residue on either the dipstick or the underneath of the oil cap. Someone who knows what they're at may have cleaned off the oil from underneath the cap. The dipstick would be a dead giveaway.

The mayonaise is caused by oil and water mixing or "emulsifying" as it's properly known under extreme heat and pressure.

Sounds like a big deal to me anyway... Really big. Get a mechanic to check the car over before you buy it. If the head gaskets gone and you can't fix it yourself it'll cost you up to £1k.

Or even worse, the head itself may also be cracked which will add even more cost to the repair.

Good luck mate.... Tread very carefully.

Mon Apr 20, 2009 1:09 am

Mine lost it's heat but it was just a leaky radiator that wasn't obvious until it burst completely...

Mon Apr 20, 2009 1:10 am

Oh god this does not sound good at all! I am going to go tomorrow and check for the things you have described.

Also should the temp. be soaring if the h/g is gone? Any lack of power?

Thank you for your help mate! Really knowledgeable.

Mon Apr 20, 2009 1:12 am

yeah the temp gauge should rise aswell... where are you based? there might be a zoner nearby that might be able to help you...

Mon Apr 20, 2009 1:14 am

Does it overheat or run rough , Mix in oil/water or vice versa
The centre vents in e30s dont blow hot , None of mine have anyway .
Or could be
Low on water ?
Sticky thermostat ?
Drop the water out of it and stick a hose down both pipes for the back of the heater matrix in the engine bay , Probably blocked ??
My mates e30s heater is crap since he did a service and dropped the water out and i reckon he has a air lock or matrix is blocked .

Mon Apr 20, 2009 1:23 am

Steve-E30 wrote:Does it overheat or run rough , Mix in oil/water or vice versa
The centre vents in e30s dont blow hot , None of mine have anyway .
Or could be
Low on water ?
Sticky thermostat ?
Drop the water out of it and stick a hose down both pipes for the back of the heater matrix in the engine bay , Probably blocked ??
My mates e30s heater is crap since he did a service and dropped the water out and i reckon he has a air lock or matrix is blocked .

The centre vents don't blow hot?? Now that you have said that, the only vents I checked was the centre. (gives me a glimmer of hope lol)

Everything else you mentioned seems to be fine from what I saw. No roughness, no overheating. Drove the car for about a full 5 mins or so.

I really hope it is just something wrong with the heater matrix.

Mon Apr 20, 2009 1:27 am

Is the heater control valve not a more likely candidate than the head gasket?

If the head gasket has gone to the extent that the heater is not working, there are bound to be other visible symptoms.

Oil/water mix
Excessive pressurisation
White smoke from exhaust
Coolant loss
Overheating
Poor runnning

Without any of these, I'd be looking at the heater valve.

Mon Apr 20, 2009 1:32 am

Cheers mate ^

Fingers crossed I don't see ANY of those symtoms tomorrow morning when I go check it.

It's a shame I was going to go and pick it up aswell, left the deposit and everything. Now I have to thoroughly check before anything.

Just one question, what is "excessive pressurisation"? Rock hard pipes?

Mon Apr 20, 2009 1:37 am

where the water is not circulating, the pressure stays in the pipes... the radiotor top hose will be very hard

Mon Apr 20, 2009 1:39 am

It might be a mullered thermo

Mon Apr 20, 2009 1:40 am

yep ... that too

Mon Apr 20, 2009 1:55 am

You'll need to drive it for more than 5 minutes though - at least half an hour, I'd say to be sure.

Mon Apr 20, 2009 3:53 am

air lock?

Mon Apr 20, 2009 4:02 am

^ I'm praying it is mate.

Just read that there was a coolant filler cap recall in 1997, as the old ones would let in air... hmmmm

Mon Apr 20, 2009 7:56 am

ther is also a in line fuse for the walter solanod tuket up just in frunt of the solanoid it is ecsesacl biy removing the gluv box lokat the round solanod folow the two wiers from it about 10cm and u wil find a fuse careyer allow it looks like a normal car fuse its anps and voltige are small.

Mon Apr 20, 2009 8:43 am

Head gasket is probably the worst case scenario for a heater not blowing cold - if there are no other signs as already mentioned you can get a garage to do a "sniff test" quite cheaply where they test the coolant for the presence of hydrocarbons which would be evident if exhaust gases were finding their way into the cooling system.

If it turns out that the headgasket is OK and you buy the car its good practice to change the coolant, thermostat, cambelt, tensioner and water pump ASAP - especially if you don't have any evidence of when these items were last changed. You can flush the radiator through with a hosepipe but be careful about flushing the heater matrix as you can damage the control valve. Use a genuine thermostat when you change is as the aftermarket ones can be crap.

Mon Apr 20, 2009 10:12 am

asmith88 wrote:air lock?

Yes, this is first thing to check. In the absence of any other symptoms, this an airlock is the most likely problem.

Mon Apr 20, 2009 4:55 pm

capri_rob wrote:Head gasket is probably the worst case scenario for a heater not blowing cold - if there are no other signs as already mentioned you can get a garage to do a "sniff test" quite cheaply where they test the coolant for the presence of hydrocarbons which would be evident if exhaust gases were finding their way into the cooling system.

If it turns out that the headgasket is OK and you buy the car its good practice to change the coolant, thermostat, cambelt, tensioner and water pump ASAP - especially if you don't have any evidence of when these items were last changed. You can flush the radiator through with a hosepipe but be careful about flushing the heater matrix as you can damage the control valve. Use a genuine thermostat when you change is as the aftermarket ones can be crap.

I just bought the car !! I am very releaved to find out there are no hasket gasket issues, as there was no symptoms at all. ALSO hot air does come just, just not as powerful from the centre vents. It's just warmish air being blasted out. So I presume that will be a minor problem. Also the fan seems to make a rattling noise every once in a while at slow speeds. I was told by the previous owner I need to change the bearing on the fan? (did he mean coupling??)

Really appreciate the advice about changing the coolant, thermo, cambelt tensioner and water pump as if I hadn't read it, it would not have come to my mind.

NEXT QUESTION...

How much am I looking to pay for them parts mentioned above? Don't want to get extorted by sly mechanics. Also where can I get these parts from???

MANY THANKS.

Mon Apr 20, 2009 5:01 pm

Congratulations on your purchase fella - get some pics up ASAP

If you're competent enough to change the parts yourself ( not too difficult - just requires basic spannerwork ) I would probably get the Thermostat and Cambelt from a main dealer and the water pump and tensioner from Euro Car Parts or GSF ( but check the main dealer prices for these first - if theres not much in it you may as well buy the genuine stuff )

You can try your luck at getting a discount from a local dealer, or post in the parts section of the Zone and Cotswold will give you a discounted price delivered to your door.

If you're talking about the heater fan making a rattly noise loads of them do that - you can live with it and it will work for ages or change it if you fancy pulling the dash apart

Mon Apr 20, 2009 9:45 pm

Cheers pal.

I will get them parts changed asap. I can imagine the car running very nicely when those parts are changed so I can't wait. I am going to be keeping this car for a LONG time so its worth it.

Pics will be coming asap.

Bits to sort out are:

Viscous fan... it wobbles and rattles (coupling?)
Idle control valve... idling up and down
Smell of fuel inside the car, only SOMETIMES. I'm clueless?? could be caused by the funny idling.
Change parts related to cooling system + cambelt, pre-tensioner.

+ a full service.

Fingers crossed should be very sweet after that.
If anyone got any advice for the above issues, any help will be great.

Mon Apr 20, 2009 9:50 pm

Secondhand Idle control valves sold here cheap regularly in the parts section - Chris-W will have one.
Viscous fan you're probably best with a new one
Smell of fuel will almost certainly be perished fuel pipes in the engine bay - cheap enough to fix just a bit fiddly

You can get it running smoother by cleaning out the throttle body with carb cleaner as well

oh and...

Mon Apr 20, 2009 11:43 pm

Smell of petrol will hopefully be a perished breather pipe that goes through the offside rear wheel arch. Remove wheel, remove cover and you will see it. Fuel pipes under the bonnet are under pressure so you would soon know if one of those split

Otherwise tank could be on it's way out which is quite a big job to change.

Idle control Valve (ICV) take it off and give it a good spray through with 'carb cleaner' available form all good motor factors.

Centre vents on E30's only blow hot air when the temperature control knob is turned fully to the hot setting. at all other posistions they blow cold to keep you alert while your feet keep toastie.

What your friend was probably talking about originally was that if the coolant system is not bled properly after a coolant change etc then it can lead to headgasket failure, head warping and cracking. If the coolant system is not bled properly, the heater will not blow hot

Enjoy your new toy, then start spending money on making her lat for years to come.

Chris

Mon Apr 20, 2009 11:56 pm

Congrats on owning a E30 mate enjoy many years of motoring!

Tue Apr 21, 2009 5:21 pm

Thanks guys! I feel very welcomed!!

I got some VERY QUICKK snaps for you guys:

Will take much better ones later on today with the top down.

The kit needs a respray, little rust spots underneath the back bumper, and thats it.

Just found another issue though

Coolant keeps dropping. This is the second time I have topped it up and it keeps dropping to the exact same low point. Coolant light has come one once yesterday, filled it back it to the mid point where the bottom half and top half of the tank meet. Checked the tank again today and its gone back to that low point again. Coolant light hasn't come back yet though.

Radiator looks new and very clean, no signs of puddles or wet patch under the car when parked up overnight. No signs of head gasket. I'm hoping its just a leak in a pipe somewhere. What can be the source of this and what do these symptoms sound like?

Your a helpful bunch so I have faith in you guys lol.

Thanks.

Tue Apr 21, 2009 5:32 pm

ARE any of your carpets wet !!!!!! as this has heater valve written all over it !!!!
Another thing if you use a pice of card under your car over night to see if any coolant is dropping as you might have a duff rad.
WHAT does the tempurature gauge do when you are driving ?????

Tue Apr 21, 2009 5:47 pm

Heater valve? Could be!

Temperature is always bang on the middle when its fully warmed up. NEVER over.

I'm going to check if passenger carpets are wet. Also as I said, radiator looks very clean and good condition from what I can see, but you never know what lies beneath.

Tue Apr 21, 2009 5:48 pm

check the passenger carpet as that is where the heater valve is located

Tue Apr 21, 2009 6:04 pm

Just checked and your right!!

It's wet, but its not so wet that I can feel it with my hands. Can JUST ABOUT feel the wetness on certain parts, but I can definitely SEE that it is wet. I have a very thick carpet with foam padding on the underside, so its hard for water to soak through. But the dead giveaway is that there is dark patch all around the passenger footwell! Tried brushing it up and down with my hands, and the dark patch is still there.

So its just a simple case of New heater valve.?

so glad the problem has been identified, literally in minutes! And its nothing major. Thank you Fowler.

Tue Apr 21, 2009 6:45 pm

looks cool mate

Tue Apr 21, 2009 6:47 pm

yes it is a reasonably easy job where are you located

Tue Apr 21, 2009 8:11 pm

Got some better pics

I'm based in London mate.

Tue Apr 21, 2009 10:42 pm

Had very similar problems with my e30, warm but not hot air. I change the heater valve but it didnt fix the problem.(although i didnt have a wet floor) It turned out that the heater matrix was blocked. I fitted a water hose to one of the pipes in the bulk head and turnd the water up full blast, kept hose on till water that was coming out was clear started her up and bobs your uncle, hot air. Hope this helps

Tue Apr 21, 2009 10:50 pm

Looks like a nice car mate.

If it looks like it has a new radiator recently there could be an air lock in the cooling system as its slowley working itsself out the level is going down.

Try bleeding the system it only takes a couple of mins.

Tue Apr 21, 2009 10:55 pm

Cheers fella. Will get someone to bleed it for me tomorrow. Any tips how to avoid getting air locks while doing it?