Help!! No Front Heat in Winnipeg!!

[pj_jazzy_janz]

So, as winter kicked in, the front fan kicked out. This led to a few fogged and frosty windshields, much cursing from my wife, and one or two white-knuckle drives through the city. I have since opened it up and (after finding some fantastic advice around the forum) knocked the fan around a bit, which worked like a charm!!
However, I now notice that the fan is blowing only cool/cold air. As it's still unseasonably warm here in Manitoba (-5ish), I don't think my wife has really noticed that part yet - she's still just happy the fan works. But eventually, it's going to get proper cold here and then we'll be in real trouble. Any advice on what/how serious my problem is and how to go about fixing it? I do know there is a small coolant leak that is as-of-yet undiagnosed - maybe they're related? I'm pretty (extremely) new at this whole "fixing it yourself" thing, but I likes it! I'm not afraid to get in there, as long as I know I can get back out again in a fairly reasonable timeline - we need the van to get the whole family anywhere.

Any ideas? Is this a "bring it in" kind of problem or one I can tackle myself?

[Big-Bird]

You have heat at the rear box correct? So that would make me think the thermostat is working properly....(if you have no rear heat then the thermostat is done...easy fix...takes about an hour to R&R it) and the cost is under $50 for the part.

If you have rear heat then here's what to do next....

1) First thing to check is there heat at the hoses (firewall side) that lead into and out of the front heater core. You will need to move the intercooler if your Deli is a diesel just to see and touch the small diameter hoses. If there is HEAT on both hoses then your heater core is likely okay GOTO STEP 2. If the heater hose is cold on one/both sides then there is no flow and the heater core is blocked/plugged. (GOTO STEP 3)

2) Check the flaps that actuate the various air flow baffles in the heater box. If your system is cable operated see if these cables are still attached to the flap controls. Remove the glove box completely to get a good look at the system. The GB is held with 3 or 4 screws and a pair of plastic stops that just slide out of the bin sides (empty the GB first and then pull the slides which will expose the phillips head screws). If you have an electronic system then there is likely a controller error but I think it too actuates the baffles via cables. ( mine is old school so can't be sure )

3) If you have no heat at the heater core hose(s) you have a big job a head of you to R&R the heater core. I have done it and so has Macro this month infact....I did mine in 8 hrs. It was likely the same for Macro. There is no valve to control the coolant flow...this is all done with flaps/baffles in the heater box.

[pj_jazzy_janz]

Big-Bird, you are a phenomenal human being!!

While I do generally trust my children (they're the ones who told me it still gets warm in the back), I think, with all the work that can be saved, I'll do my own tests back there.

I had actually read macro's thread a couple of times and pitied him like Mr. T with a fool - sounded awful!! Here's hoping it's not that...

[Big-Bird]

R&R of the heater core is very long job...some say its hard....I think doing an engine rebuild is hard...this is easy by comparison but it will test even the most patient of techs.

Lots of screws, nuts, bolts, and trim clips.

Remove the steering wheel colum trim and intrument cluster.
Some L400's have a binnacle on the dash...remove that too.
remove the glove box and dash mounted AIR-BAG or junk tray...depends on the model you own. There are bolts under these that hold the dash in place.
The radio, heater controls, ashtray (entire middle section) must be removed.

There are 2 side trim parts between the dash and the B-Pillar (little traingle window) that need to be removed too.
Heater core hoses are usually stuck solid on the heater core...almost always have to be cut free or you risk twisting the brass tubes of the heater core.
The dash can be pivoted up towards the windshield which does allow enuogh room to pull the heater core box. A prop rod (stick) is useful here.

[pj_jazzy_janz]

Oh good. Patience is my specialty.

Can't wait 'til I realize I should have been keeping track of all those screws, nuts, bolts, and trim clips when I try to put everything back...

[Big-Bird]

If you do have an AIRBAG in the dash its highly advised you disconnect the battery (batteries?) so that the airbag doesn't go off by accident when being unplugged. Its unlikely this will occur but better safe than sorry.

[macro]

Yep, can confirm the heater core is a real bitch. I wouldn't call it difficult, just extremely fiddly. I still haven't put all of my dash trim back on because I was so sick of it. If it turns out to be your heater core I would order new hoses and clamps too (I'll try and find the part number). They were cheap, but there was no way I was going to get those hoses off without cutting them.

If you need pictures of what needs to come out (everything) PM me and I'll help with what I can!

[macro]

Oh good. Patience is my specialty.

Can't wait 'til I realize I should have been keeping track of all those screws, nuts, bolts, and trim clips when I try to put everything back...

For the first time ever, I put screws and trim plugs in ziplock bags and labelled them and taped the bag to the trim piece. Highly advisable!

[pj_jazzy_janz]

Well, I looked at it this weekend and it looks like the heat in the back is not working as well as my children would have had me believe. So I think I might be able to save myself a little pain and aggravation!! I figure it's worth swapping the thermostat to find out. Now we just hope the weather holds out until I can get to it...

[thelazygreenfox]

You can try bypassing the heater cores with short sections of copper tubing then check the water temp at the bypasses. Do the front first with the engine cold.

Carefully pull the hoses from their connections, insert the tubing and clamp closed to prevent any leaks. Run the engine to temperature. If the thermostat is working the hoses will be hot. If cold then the thermostat is faulty. A laser temp probe is invaluable at this point. Just point and read the temps.

Your heater cores could be plugged too. A step by step process will eliminate the problems. It's not perfect troubleshooting but consider it before starting. The heater cores can be pickled with a light acid water mix for a day then backflushed at the same time. Some debris will be removed and the core will produce a little more heat.

I'd backflush the core with water pressure first, then bypass the core with tubing.
I hope that makes sense .

good luck
TLWF

[Big-Bird]

I forgot to ask where does your temperature gauge needle sit when the engine has been running for 15-30 minutes?

the needle should be at half way on the gauge even at idle. If your needle rides lower at idle your thermostat is done as its likely open and not keeping proper coolant temperature.

[pj_jazzy_janz]

It sits dead centre. Does that mean it's not the thermostat and I have hours of dismantling and re-mantling ahead of me? Or could it still be the thermostat if the needle is where it needs to be?

[pj_jazzy_janz]

Fox, that's all a bit above my pay grade. Sounds very helpful, but also quite out of my league.

[Big-Bird]

PM SENT.

[Big-Bird]

Seems our Winnipeg Deli owner has been too busy with lil' ones to post an update but after a short Skype tutorial Phil was able to find their problem.

Low coolant and an air lock in the system. Now they have heat for the winter ahead....but why was it low you ask?....Phil has to perform a coolant system pressure test and locate the source of the coolant loss....nothing on the ground points to a head gasket but the test will confirm.

Stay tuned Deli fans! More to come!