Climate control system crisis

[michaeld]

benzlover,
Ya know, I'm not sure.  I thought it was the upgraded model, because there is an aluminum band around the middle section (like on the unit that JCCP photographed above).  The bottom section (where the hose attachments are) is definitely plastic.

I'd like to know more about the option of buying an "indestructible" servo.  If I'm going to replace the thing, then I'm going to get something I only need to replace ONCE.  Otherwise, it's bypass or electronic option.  The electronic unit offers a five year warranty.

I'd prefer to have my servo busted to my heater core, as the thought of crawling up the dash to get to it leaves me wimpering in a corner...

But here's the happy-happy news in Mikey's otherwise currently bleak w116 universe.  I won the bid on the two volume "chassis and body" manual for $31 + $6 shippping.  I've been trying to find one of these forever for anything resembling a good price, and finally got it!

Happy is the DIY who has a manual, for he finally has some vague clue what he's supposed to do...

I'll compare the paper manual with the cd, and write a future post on what is same-same/different.
Mike

[michaeld]

I got around to doing some of the diagnostic stuff last night.
First, I performed a resistance/temperature relationship test on the water temp sending unit.  I was bummed when the thing checked out fairly accurately.
At 60C/140F  it was 107 ohms (cf spec 110)
At 80C/176F  it was 63 ohms (cf spec 67)
At 90C/194F  it was 47 ohms (cf spec 51)
At 100C/212F it was 38 ohms (cf spec 38).
I was told the margin was +/- 4 ohms.
No way the sending unit was causing false overheat readings on the gauge.

Next I checked the sender unit while connected to the gauge.  This was a little trickier.  At first I got the gauge to read 250F +, but then I realized that my aligator clip was touching the post - and that the sender will always max out the gauge if that happens.
I wrapped some wire around the sender to give me something to clip a ground wire to (other end to battery), and the readings were more normal.  Unfortunately, I could not put 212F water into a container and get that container into the engine compartment to stick the sender into.  By the time I did all that, the water was no hotter than 190F.

At a measured temp of 190F, the console gauge read 175.  And it continued to read 175 until the actual water temp was in the high 140s.  I found it more than a little weird that my console gauge would read the same temp through a 40 degree difference.

But that doesn't really help me figure out my overheating gauge problem, since the gauge did not read excessively high - and in fact, w/ the actual water temp at 190F, it actually read low (at 175)!.

I'm going to have to figure that I may really have been driving hot all this time after all, unless someone can take the my data and create a "bad gauge" hypothosis from it.  Dang.  I was really hoping something was wrong with that sending unit, or at least the gauge system.

Tomorrow, I guess I'll start the car up and let it get hot to see where the coolant flies out of first.  I've got one of those UV-based dye kits to help me find leaks - and if I don't use it now, I'll never use it.  If possible, I'll take the hose off of the expansion tank to test the water pump (does anyone have a better test for a water pump than that?  I figure if it's working, I ought to get water flow into the expansion tank.  Obviously, the thermostat has to be open for that test to work.

Whenever I turn the key to the "alt" position, my ACC servo is gurgling (basically making unhappy sounds).  That tells me there's something wrong with it now - but to be honest with you I never really turned the key to "alt" until now to now that for sure either.  Does a happy servo make any noise when the key is turned halfway, or only a sick, dying servo?

[jjccp]

Michael,

I don't think the sound from the servo really tells you too much. If it's leaking/cracked, it's junk regardless of the noise.

I have two 116's. On the 280 SE the climate control and servo (except for A/C) has worked fine for the 20 years that I've owned it. The servo makes a buzzing sound whenever running and for about 30 seconds after the engine is shut off.

I'm currently working on the 6.9 and that car now has the newly rebuilt servo. BTW, I don't think there is a bulletproof servo. The photo of mine with the aluminum case is before the rebuild. It now has an even better new aluminum bottom part also. That's the part where all the coolant hoses connect. So I think rather than bulletproof, it's less likely to crack, in it's new form. There's still tons of crap to go wrong inside of the servo.

Here's a little more info for those of you looking at upgrades or options. Even though I have a new rebuilt servo, I still don't have full function of the climate control system. I'm now working on tracing a vacuum leak and have the controls (buttons) all taken out and I'm working on testing the vacuum switch array behind the dash. This is  totally uncharted territory for me. The guy that rebuilt my servo is helping me trouble-shoot the system via email and pictures. Otherwise, I would have no clue in the world how to fix it.

Have you ever seen what's behind the heater controls? There's a whole world back there.



Remember that whole system can be a major nightmare. But I still love working on these cars. It's not like I actually have a life or anything.

Jim

[michaeld]

JCCP,

Boy, that's a terrifying-looking world!  I sure hope my heater isn't the culprit, as I cringe at the prospect of tearing it open and trying to figure it out.

My plan is to bypass as necessary and see if that fixes my old overheat (not to mention my new leaking) problems.

I have a question: I can simply turn on the engine and see what leaks where (I have a UV leak detection kit).  Or I can use a pressure tester and see if I can generate a leak.  OR I can hook up a pressure tester AND run the engine.  How would you go about finding the leak?  And what would I be looking for if it (gulp!) is in my heater?
Mike

[Papalangi]

Hmm...

Not many things left to check.

The wiring diagram shows a shared ground for the tach, fuel gauge, clock and the temp gauge.

Does everything seem OK with these or do they sometimes act a bit strange?

The gurgling may come from the aux water pump which comes on if the engine is running and the in-car temp is below 79F

It may turn out that your engine runs hot.

You will need to run the engine to distribute the dye but then you can use the pressure tester or run the engine to look for the leak.  You'll have to do something like pull the upper radiator hose to get the dye into the cooling system as putting it in the recovery tank won't really work.

You could also just hook up the pressure tester without bothering with the dye.  I would use the tester rather than running the engine because it will get hot and the pressure will take sometime to drop with the engine running.

Michael

Michael

[michaeld]

Papalangi,
Hey, buddy.

Just so you know, I DID pick up those clamping probe tips you recommended, and they DID come in handy.  I went down to the radio shack and got the kind that stick on over your probe leads (that's all they had in stock or I would have got the type that included the wires).

I don't really even look at my clock, but no, my other gauges have always been pretty accurate.

I'm pretty darn sure that the gurgling is coming from my servo, as I had my ear to the darn thing while it did its gurgling. 

That's intresting that you don't think sticking the dye in the expansion tank will circulate it through the system (though I'm willing to trust your judgment on that). 

And yeah, I guess I'll go down and get the pressure tester and hook it up so's I can see what I see.  And just so's we're all clear, what would I see if the leak was coming from my heater core?

I'll also need to pick up JCCP's copper tubing (not sure of the size quite yet, JCCP), but I wanted to see where the leak is coming from first.

And back to the gauge, what does it mean to have a gauge constantly read 175F whent he actual water temp starts at 190F and cools down to 148F before the needle budges?

Has anyone hooked up an alternate/auxilliary gauge?  Were you able to use the stock sending unit, or did you have to get a different type?

[Papalangi]

It's good to be back.  Since all hell broke loose Thursday night here in Seattle, I've been suffering from internet withdrawl.  Just got back online at 9PM Sunday night.

I have a kit of test leads that includes and insulation piercing probe which can check a wire anywhere along it's length.  Very handy.

If you here gurgling in the servo, I wonder if you still have air in the system.  It could be the aux water pump pushing water through the servo or the servo motor moving.  You could unplug the aux water pump and try again to find out.

The expansion tank level only goes up and down a few inches and would take forever to disperse the dye into the system.  There is no suction or flow through the expansion tank, it just gives the water somewhere to expand since it is a non-compressable fluid.  That's why you have to leave an air space in the tank.

If you have a leak in the heater core, you would smell antifreeze in the car.  Also, you windshield would probably fog up. If it's the tube leading through the firewall, you'd see it there.

If your car leaks around the windows as bad as mine does, you might have a sticky gauge.  You can gently move the pointer up and down the scale to see if it moves freely.  You might want to wear cotton glove 'cause if you touch the gauge face, the finger print will drive you nuts for the rest of time.

You can install a cheap gauge like this one,
http://www.jcwhitney.com/autoparts/Product/tf-Browse/s-10101/Pr-p_Product.CATENTRY_ID:2008847/p-2008847/N-111+10201+600002129/c-10101
Any autoparts store will have something like it for about the same price.

Yes, you will have to use the supplied sender as each manufacture uses a different scale.  Get the adapter kit, it will have adapters for a wide range of threads.

Michael

[jjccp]

Michael,

I'll let Mr. Papalangi continue to give you his good advice on trouble-shooting the engine temp issue.

I'm now testing behind the glove box for my heat/servo problem. Here's what I'm into now.



here's the climate control amplifier behind the glove box



BTW, I think I used 3/4 inch copper pipe I had laying around. Just find something that fits in the existing hoses, it's only temporary.

[michaeld]

Papalangi,
I'm glad you weathered the storm and are back in full forum glory.

For at least several days prior to my catastrophe, I actually DID smell a faint whiff of coolant - only every now and then, and only while idling - but so faint that I wasn't even sure I smelled it.

I didn't realize that the expansion system didn't freely circulate.  I'll go ahead and add the dye to the radiator via the top hose as you suggested.

I picked up a pressure tester today but didn't have time to use it.  I will first use the tester with the engine cold, and then - assuming I don't see any leak reveal itself - relieve the pressure, re-connect the tester, and  start the car and let it run until the engine gets warm.

I think I'll go ahead and pull the glove box out and have that little "peephole" to see if there are any signs of a leak coming from the heater as well.  Even if the leak is in the servo, it doesn't mean I didn't have more than one component fail.

And thanks for the info on the aftermarket gauge.  I may go ahead and buy a gauge, just to see what it's reading.  If it's got its own sender unit, that means it has its own wiring, allowing me to see if there's anything wrong.  That would also probably be cheaper than paying a mechanic to verify the gauge. 

For the time being, I'm interested in finding any leaks and plugging them.  If it's a servo or heater core, I would just want to bypass it and see if that solves my hot gauge issue.  I'll think about fixing my servo or whatever is bad after I've verified the cooling system.

BTW, I'm only dimly aware of where the aux pump even IS (I think it's under the battery box, but to be honest with you, I've never seen it).

JCCP,
I may have my own "dashboard-yanking memories" in the near future.  I've got to access the guts behind the climate control cover anyway - as my aftermarket stereo seems to have a grounding issue.  Let us pray that the patron saint of dashboard automotive repair blesses us both!

P.S. There IS a patron saint of dashboard automotive repair, isn't there?  Sometimes there are down sides to being a protestant!
Mike

[jjccp]

JCCP,
I may have my own "dashboard-yanking memories" in the near future.  I've got to access the guts behind the climate control cover anyway - as my aftermarket stereo seems to have a grounding issue.  Let us pray that the patron saint of dashboard automotive repair blesses us both!

P.S. There IS a patron saint of dashboard automotive repair, isn't there?  Sometimes there are down sides to being a protestant!
Mike

Actually, you don't have to access the guts behind the climate control cover to work on the radio. Depending on how it's mounted, the radio should come out on it's own, without removing anything else. You might need to remove the ashtray and it's bracket, but certainly not the climate control buttons. 

Less work than you thought.

[Papalangi]

The first and second pictures that jjccp posted show the aux pump.  It's the round chingas attached to the servo mounting bracket with the hose clamp.  I do not have one in my car altho there were two in the trunk when I got the car.

While I did take my servo apart and mess it up, I didn't install the ball valve bypass myself and have not opened the dashboard up so I'll let jjccp help you with that.

Since the smell was faint, I'd still be inclined to think your servo is cracked.

It's been down to the high 20's the last few days so my ball valve is around half open and I fiddle with the buttons to keep it some what comfortable in the car.

Michael

[michaeld]

Update on the current crisis:

Tried to pressure test car, but believed I picked up a failed "loan-a-tool" unit from autozone, as there was oil on the handle and the unit didn't seem to hold pressure.  Picked up another one but haven't tested yet.

I then ran the car for about 40 minutes.  I had to add over a gallon of coolant (so add that to the 2 quarts I already mentioned)!!!  Very concerned about coolant loss damaging engine.  More to say about coolant later.

But other than that... The good news is nothing happened.  The bad news is nothing happened.  I still have no idea what is leaking.  I inserted the dye (into the radiator, Papalangi) and used my UV light.  I watched for signs of leaking anywhere.  I looked inside the cabin.  Nothing.  At some point I turned the ACC control to cold/high and smelled coolant in the cabin; but it faded away very quickly and I never smelled it again.

I added coolant as I said above and left the pressure cap off the system while it idling.  I periodically checked the coolant level AND the temperature at the expansion tank (using Mr. thermocouple).  For quite a while the system was 80C/175F, but after revving the engine it climbed all the way up to 182F.  It never got hotter than that.  I shut the car down simply because there didn't seem to be any more I could learn.

Now there is something else I'v seen even before "the breakdown."  I have seen tiny bits of crud in my expansion tank.  It doesn't seem to be oil (which one would think would be black and globule-ish), but rather more like flakes that are grayish in color.  Some of it is filmy, and some of it is in tiny bits.  It is universally grayish.  I HOPE its not oil, but don't like it WHATEVER it is.  Has anyone seen this and identified it?

Another thing I did was disconnect the little hose that goes from the radiator to the expansion tank.  I was hoping that I could see if my water pump was a'pumping this way.  There was no flow.  If I understand Papalangi correctly about the expansion tank ONLY being for expansion rather than part of the "flow system," I suppose I wouldn't see flow from that hose.

Lastly, did my 40 min session rule anything in or out today?  Does the fact that it doesn't leak at idle (even after 40 minutes) mean that the heater core is ruled out?  And is there any other way - other than driving the car and having the leak-problem suddenly explode in the middle of anywhere - to find the leaking component that I KNOW is there?

[Papalangi]

There is usually a bit of gunk in the cooling system and it can settle out in the expansion tank.  I've seen an oily sheen in some of my cars and didn't worry about it unless I see what looks like mayo under the oil cap.  That is a very bad sign, usually means a blown head gasket.

It sounds like the system was never under pressure due to the faulty pressure tester and the cap not being on.  I'd let it run for a while with the cap on and see what happens or use the second tester, assuming it works.

Michael

[jjccp]

I got it all going on now boys. Just replaced the climate control amplifier and everything works - even the air conditioning. And you know how important A/C is on December 21st in Michigan.

For those of you that need to fix your system - I spent under $300 to get everything in working order. I snagged a used amplifier out of a junk yard last year for the heck of it and it works fine, so that was basically free.

Like everything, some of these repairs seem daunting, but when you get in to it, it's not so bad. Beforehand, I thought that getting to and working behind the glove box was a big deal. But it only takes about a minute to get it out, when you know how.

I'm so happy that almost everything is working well on this car that I washed it up and even put goop on the tires.

I have a first date with a lovely woman tonight - you think I might get lucky if I pull up in this bad boy??

[michaeld]

There is usually a bit of gunk in the cooling system and it can settle out in the expansion tank.  I've seen an oily sheen in some of my cars and didn't worry about it unless I see what looks like mayo under the oil cap.  That is a very bad sign, usually means a blown head gasket.

It sounds like the system was never under pressure due to the faulty pressure tester and the cap not being on.  I'd let it run for a while with the cap on and see what happens or use the second tester, assuming it works.

Dang it, you're right about that pressure cap.  I was thinking about 1) filling the radiator properly and then as an afterthought 2) taking temperature readings of the coolant.  I will have to run the car again w/ the system under pressure AND/OR pressure test it (funny story on that).

On the subject of coolant, I'm SO glad to hear that.  I suppose it's just scale.  Most of the older/classic cars I've had didn't have an expansion tank, so you couldn't see scale/lime deposits.  My coolant is and has always been a pretty shade of green - no milkshake.  And I have always been impressed w/ how clean the  in this car oil looks at change-time (i.e. not black but still amber).  As to my QUESTION, I'm wondering what my coolant staying not getting above 180F tells me about the overall condition of my cooling system (this only at idle, of course).  You expect the temp to get to 176F because that's my thermostat temp.  And even w/o the pressure cap on it could still get to 212F.  Does this tell me my water pump is functioning properly?  Etc. w/ the other components? 

I have a new plan of attack: I will tear out the glove box (I just received the w116 body & chassis manuals I got on ebay so it will be fun to play with my new books) and check for signs that the heater core or hoses has failed/leaked.  If I see nothing I will assume the servo failed and bypass it - even if I can't get the leak disaster/failure to repeat.  I will certainly re-test the car w/ the system pressurized AND will try to get my hands on another pressure tester.

I also bought a water temp gauge.  I'll have to drain the system partially to install it, but once I find that leak, I could just leave the gauge in the car (rather than route it through the firewall) and periodically check it by opening the hood in order to check my temp.  If I'm hot, I'm through screwing around and will take the car to "MotorWerks."  If I'm cool I'll figure my gauge was bad all along and properly install the unit.

As to the pressure tester, I returned the one that had leaked oil through a bad seal last night and picked up another.  When I tried to install the second unit, I could not get it to clamp on and pressurize.  After screwing around for 15 minutes, I inspected the cap on the pressure tester.  Someone had either dropped it or banged on it (and it looked like the latter) such that the cap was slightly warped.  So I brought it back today and showed the clerk what I'd found, and she asked me if I wanted to try a different one.  Why, yes, I would.  So she brings me ... the same one that I'd brought back the night before.  I saw the oil on the carrying case.  I'll have to get to another AutoZone to get a loaner, or spring for $80 to buy one.

JCCP - if you don't "get lucky" w/ that 6.9 looking like it does (and w/ A/C to boot!) then none of us has any hope.  You're our star!  Don't let us down!
Mike