e34 Heater problem

[onlyasking]

Hi all,

I'm a first-time poster here, and not a major DIY talent. I've fixed a few relatively simple things on my 1993 manual 525 (m50).

The current issue with my heater has been covered by other posters, but I'm still reluctant to (a) take on the onerous task of removing the dash, remembering where everything goes etc, (b) pour in radiator flushing/ leak-sealing products which may do more harm than good, or (c) spend a whole lot of money.

The problem has arisen in recent cold weather. I'm struggling to keep the windscreen clear, with a halo effect from the film of coolant on it, a strong smell of coolant, and on one occasion even some evidence of coolant on the exterior of the screen. It doesn't matter what I do with the heater/blower controls, I can't keep it clear in cold or wet conditions.

When I shut off the three slider controls I can see steam coming out of the dashboard and door vents as the engine reaches operating temperature. I've had a look in the engine compartment for any sign of vapour when the engine reaches operating temp, but there's nothing by way of visible steam.

There's no visible sign of a coolant leak in terms of wetness in the carpet or anywhere else.

The heater still works normally in terms of provision of heat, but not being wrapped around a tree is obviously more important than being warm.

Coolant loss is significant if the heater is in use, and less so when it's off, though there has been some abnormal coolant loss since I bought the car a year ago. The sudden worsening of the situation has only recently occurred.

Obviously I'd like it if a radiator leak-fixing product would do the job, or ditto for a radiator flushing product. I've seen warnings about possible sudden dumping of boiling water on my feet if the wrong course of action is taken, so I'm nervous about just "giving it a go".

I really don't trust myself to take the whole thing apart, and I'm reluctant to pay several hundred Euro for someone else to do it, so the last option is to bypass the heater. Is this as straightforward as it appears?

I love the E34, this is my second following on from an automatic 520, and I'd like to keep the beastie going for a while. I know the heater is one of the weakpoints in the machine, but it is almost 16 years old. The engine is phenomenal BTW, with 165,000 miles on it.

If anyone out there can advise me on the best course of action I'd be very grateful.

All the best.

[Ross]

It is straightforward but time consuming and you may find yourself disassembling stuff you didn't need to.
Nobody likes this job but it is just a nuts and bolts job. If you do it yourself you will; A. Have the satisfaction of having done it. B. Save a load of cash. C. Have the opportunity to clean out the coolant residue so you wont be smelling it forever.
Plan on a stiff drink and maybe a chiropracter visit after.

[onlyasking]

It is straightforward but time consuming and you may find yourself disassembling stuff you didn't need to.
Nobody likes this job but it is just a nuts and bolts job. If you do it yourself you will; A. Have the satisfaction of having done it. B. Save a load of cash. C. Have the opportunity to clean out the coolant residue so you wont be smelling it forever.
Plan on a stiff drink and maybe a chiropracter visit after.

Thanks for the reassurance Ross.

Am I right in thinking that your reassurance regarding my ability to do the full removal means that there's no possibility of a "quick-fix" i.e. sealant for leaks or flushing for blockages?

[DaveVoorhis]

there's no possibility of a "quick-fix" i.e. sealant for leaks or flushing for blockages?
That's right -- there isn't a quick-fix. It's a tedious job that will have you yawning with boredom between bouts of puzzling where to put all the removed bits (I recommend the kitchen, so you can involve the missus in the shock value), but it's actually very easy.

[Ross]

There is always the possibility of that working. I'm not a big fan of cures in a can and always prefer the correct fix. Especially if someone else is doing the work!

[onlyasking]

Ross and Dave,

Thanks guys. It looks like it's the big job then. I can't wait.

There goes a weekend.

I'm much obliged for the clarification.

[Ferret]

Another job that needs doing on mine *sigh*

Mine will stabilise for about a 2-3 months with a can of radweld or the like, but it's by no means a permenant fix!

Yours sounds like it's a massive leak if you can physically see steam coming out of it :( there's no way a one-shot can of something would sort that out...

[onlyasking]

Another job that needs doing on mine *sigh*

Mine will stabilise for about a 2-3 months with a can of radweld or the like, but it's by no means a permenant fix!

Yours sounds like it's a massive leak if you can physically see steam coming out of it :( there's no way a one-shot can of something would sort that out...

I'm girding my loins in preparation for the task. I don't have an indoor space for the job, and it's pretty cold here in Ireland at the moment. Oh, for a garage.

I bought the car last June to replace my old 520 auto, which was (a) in need of a steering rebuild, (b) was two years into a transmission repair, and (c) was showing signs of heater problems itself. I decided against spending money on the steering in case the other problems reared their ugly heads shortly after.

I got the 525 for a snip, replaced the rear shocks and top plates, and took the car absolutely chock-a-block with camping gear plus wife and two teenagers across France and Spain without a hitch. Those extra horses helped in pulling that weight for about 3,000 miles. What an engine.

I love these cars, but I'd love to wake up tomorrow with the heater job done and dusted.

All the best, and good luck with the job :)

[vping]

When I was 16 and still green, I ahd a 77 Trans Am with a bad heater core. Got my feet with this car and tackled it myself. The heater hose clamps were up behind the inner fender and the only was to get to 'em....take off both the inner and outer fender, not to mention the majority of the dash. Taking the time to do it right beats then hell out of the green pond that was accumulating on the passenger floor.

You can do it and will be succesfull.
Cheers

[Gene in NC]

There's another way. Block off hoses to and from the heater and run without it. Dress warmly. Not elegant but puts work off until better weather. Get a can of windshield "melt" for frost to take care of the defrost setting.

[Kibokojoe]

Its heater core time. I have changed out a few heater cores over my lifetime and my 89 535i was one of the easiest. Pull the console, glovebox and knee panel then the panel over the core. Took me about 2 hours all together. Toughest part was paying $150 USD for a heater core :) The reason the carpet is not wet is that there are drain holes under the core, fortunately for you they are not plugged.

[angusbn]

So do you any instructions for replacing the heater core on a 89 535i - glad to heard you say it's not too bad to do. I thought that the entire dash needed to be removed.

[angusbn]

+1 - any more thoughts?

[Kibokojoe]

Never seen any instuctions on removing the heater core. I guess because most owners have pulled the center console and its just under the cc. Haven't looked to see if there are any instuctions on removing the cc. The only problem I had was I lost one of those little c clips that hold the heater core cover on. Do a search on here for console removal, as far as the heater core it is pretty intuitive. I will look around and see what I can find. Been busy replacing a driveshaft :)

[Kibokojoe]

Here is my instruction on pulling the knee panel

http://www.bimmernut.com/forum/showthread.php?t=39242

[Kibokojoe]

Here is shoguns instuctions but no pics

http://twrite.org/shogunnew/topmenu.html

Then go to
1. fixes
2. heater and A/C
3. various

Look for shoguns article

Heater core, remove and replace: no photos

[angusbn]

Thanks kibokojoe for your assistance.

Just to reconfirm that only the center console and glove box need to be removed and not the knee panel? As you said the core is in behind the center console. Does removing the knee panel help with access?

Sounds not too bad on the '89 535i and I'll look to tackle it in the spring. I need to go in to fish out the blower resistor sword so I'll be in the neighborhood.

Thanks bud.

Blair...

[Kibokojoe]

knee pad removal helps get to the side clips on the heater core cover. Knee pad is not that hard to remove takes about 10 minutes at the most. Just keep all of your screws nuts and bolt separated. I use plastic butter dishes :)

[angusbn]

Thank again. A new heater core is $214 Cdn with gasket rings so not too bad.

As an aside, I'm going to attempt to rebuild the blower resistor MOSFETs so I'll be saving $$ doing that so I'll spend it on the heater core.

Can't do anything until its nice enough to work outdoors in the spring - no garage.

Hope my 17 yr son who's about to inherit the E34 appreciates all the work and $$ I've invested.

Blair...

[Kibokojoe]

He will. I just bought a 91 735i for my son. We spent about 3 hours changing out a driveshaft and it was -11 degrees Fahrenheit. But then again we had a garage :)

[angusbn]

Hey kibokojoe, did you also replace pipes #2 and #3 (coolant in) and #4 (coolant return)?

Did you replace the two o-rings #18 in the diagram?

What I saw was coolant dripping at the rubber grommet #16 where pipe #4 nipple extends thru the gromment. I read somewhere that these three pipes were NOT a wear item so I suspect the o-rings #18 are the culprit or it leaking somewhere around the core and gravity is cauing it to drip lower?

Blair...

[Kibokojoe]

I replaced only the core and the orings. Did not replace the pipes

[angusbn]

Thanks. That also included the two o-rings #18 in the diagram?

Thanks for your assistance.

[Kibokojoe]

Orings on the core and orings on the pipe

[fin]

I just pulled the glove box, center console and knee pad to fix my heater core problem. (smell and fogging windshield on driver's side) It's a long process, but not necessarily difficult. Not loosing the little metal clips is the hardest part.

All I had to do was replace the three O-rings and it fixed the problem. I didn't put it back together until I knew that the O-rings fixed the problem.

The heater core looked scuzzy on the driver side half and I thought the it had corrosion had eaten through the core. Instead, the coolant trickled down the interior side of the core leaving the firewall side clean.

So don't buy a heater core without pressure checking the old one first. Doing that could save you big bucks.

By the way, my old O-rings had a square cross-section instead of round. More than likely the root of all these heater leaking repairs.

I took pictures with things apart. I need to resize them so that they can be posted. Should they be posted on the wiki sight? PM me if someone wants to do that.

Hope this helps,

Fin

[angusbn]

Thanks for your post.

I suspect that the o-rings are my problem but won't know until I have a chance to open it up in the Spring (I park the car in the winter).

If you can post your pics that would be great.

Blair...

[Kibokojoe]

Post the pics please

[onlyasking]

There's another way. Block off hoses to and from the heater and run without it. Dress warmly. Not elegant but puts work off until better weather. Get a can of windshield "melt" for frost to take care of the defrost setting.

That's the kind of advice I like. I'm the great procrastinator, see ya later!

Of course, without a lockup that kind of job is a nightmare in the cold and rain, and I simply won't attempt it. In fact, I had a car a few years ago in which I did the bypass, dressed warmly (and a little inelegantly) until spring came along.

[onlyasking]

Its heater core time. I have changed out a few heater cores over my lifetime and my 89 535i was one of the easiest. Pull the console, glovebox and knee panel then the panel over the core. Took me about 2 hours all together. Toughest part was paying $150 USD for a heater core :) The reason the carpet is not wet is that there are drain holes under the core, fortunately for you they are not plugged.

Thanks for the upbeat assessment. I'm going in, but not just yet. It's raining here in Dublin (q'elle surprise), 4 degrees C, a little windy, and the days are still short.

As soon as I get a slightly warmer Saturday or Sunday, with little wind and 6 hours to spare, I'm going to do this thing.

All the best, and I hope your kid appreciates what he's getting. My second-in-command is turning 17 in the summer, and he wants to go down the BMW route as well.

[fin]

onlyasking,

This is an inside job.

Inside the car that is. Plug in a portable heater (preferably one with a 'tilt' switch to turn it off if it falls over) before you are going to work on your car. No need to have your head under the dash much so you can keep the car doors closed.

I did this job in -5C weather, winds gusting to 20kph and snow. I ended up working in shirtsleeves for most of the time. It was nice and toasty with the 'milk house' heater blowing hot metal smells all about.

In the states we have a perception of the Irish being tough as Bog Oak. Please hold up your end of the deal. Don't make me call you a 'girlie man'.

As I didn't check your profile and you are of the feminine series, don't make me call you 'prissy'.

Cheers,

Fin

[Kibokojoe]

Yes a milk house on the back seat with a piece of plywood under it. Its out of the way and I ran the extension cord out the window with a towel to fill in the crack. This way I did not mess up the door seals :).

[Kibokojoe]

Buying a 7 for my son has turned out to be a really good investment. Not only is it a great car but we enjoy working on it together. Great father son time. If your looking for a way to communicate with a teenager there is no better way. Nothing can beat laying under a car with temperatures below zero, a torpedo blowing heat up your pants leg and getting greasy together. And I thought I was just buying him a car :)

[adrian.j]

if any one has the slightest idea... i have a 92 e34 and my heat only blows on high all the other settings dont blow at all,, also the heat doesnt get very hot but it does heat the car up after running for a little bit.. could you tell me what this might be and how much you think it would cost to fix

[Kibokojoe]

Sword or resistor on the blower speed. As far as the heat, I would check the heater valve to insure it is working properly. I recently had my coolant system flushed. Artieries could be clogged.

[adrian.j]

Sword or resistor on the blower speed. As far as the heat, I would check the heater valve to insure it is working properly. I recently had my coolant system flushed. Artieries could be clogged.

how would you clear that up

[Kibokojoe]

If you can't afford a coolant flushing at a shop in a pinch I have hooked up the garden hose to the inlet of the heater core. Disconnect the inlets and outlet to the heater core. Plug the lines or raise them up so you don't loose any more coolant than you need to. Hook the garden hose up to the heater core inlets and and let the water blow out the heater core outlet. I did this on my 89 Honda accord and it worked. I was amazed at the crap that came out of that little heater core. Has anyone on this forum done this on a bimmer in the past? My understanding of the heater core on the 535i is that there are two separate cores built into one. So you will have two inlets but I believe there is only one outlet. Is this correct guys? I recently had the coolant on my 5 done for $50 USD. It was worth it.

[angusbn]

Hey kibokojeo and fin,

What size O-rings did you use?

Realoem.com shows three different sizes (13.98mm, 20.29mm*2 and 17.12*2).

Thanks.

Blair...

[Kibokojoe]

Go to this site. Its easier to use than Realoem.

http://bmwfans.info/original/E34/Lim/535i-M30/USA/L/M/1988/10/mg-64/ill-64_0174/

Anyway I replaced seals 8, 9, 18

[angusbn]

Did so, thanks. $7.50 is parts for the 5 o-rings and $15 shipping fee to up here. Ordered from BMA Parts.

[Kibokojoe]

Man where do you live?

[angusbn]

The Great White North (strong and free). Ottawa, Ontario, Canada.

It's only money.

Blair...

[Kibokojoe]

I have two kids a wife and a mortgage, Haven't had any money for years ;)