108 heater valve repair (AGAIN!)

[Tomguy]

Ok, so the inadequate heat pissed me off. I took the glovebox out and I saw that the valves would close all the way but not open all the way - the lever would contact the retainer for the cable with about 1/4 of the travel left for the valve. (On both the driver's and passenger's sides). See the pic - the drawing shows where they stopped when they should have been on "full"

I believe that the valves were in the wrong way, so to make 100% sure I get this right, I want details!

(Pardon the pics ****ty quality, all I have is a webcam, no digicam)

Does groove 1 normally have an O-ring on it? Mine doesnt but it kinda looks as if it should...

What position does the opening (#2) point when the valve is completely open (for the right, pass lever, does it point up, down, left, or right? Same question for the left, driver's one, that I don't have out yet).

[psfred]

Yes, there should be an o-ring in the groove. Probably leaks if not, either around the valve or out onto the floor like mine.

I haven't pulled mine yet (maybe next week if the Volvo starts in the next couple days).

However, if you can see into the valve body, the openings must line up correctly for proper flow. I'm sure they can only go in at 180 degree positions, so they are correct or backwards, right?

Also, if you have a clogged heater core, it won't matter how far open the valve are, the heat will be inadequate. Was there a lot of crud in the valves? Scale can be removed with citric acid (I'm doing a citric acid flush as soon as I get a clear garage). Backflush can help, too.

Also, you need to get all the air out when you fill the cooling system, and this is a pain. Usually have to open the connection between the long pipe and the heater core to "burp" it.

Poor milage can be overcooling (the cold enrichment stays on til 175F) or just a vac leak or need for adjustment. Get the ignition up to snuff (and make sure the vac retart works right), then take care of any vac leaks, then fix the mixture. Note that if the vac retard isn't working, you need to set the ignition timing at 7 BTDC, not 5 ATDC or you will get sluggish performance and lousy milage.

Peter

[Tomguy]

Actually, I don't think that groove is supposed to have one after looking at how impossible it would be for it to go into the housing. The other ends do have a O-rings on but I want to replace them. I wonder how difficult it will be to find the washer that goes into the smaller brass piece though (the quarter-sized one that goes around the shaft to seal it). I think a factor in poor flow would have been the fact that the narrow spot (to the right of #2) was completely gunked up (on both valves) to the height of the valve ends themselves!

The car does indeed get to 175 now and stays there, but I wanted to check the WT sensor to make sure its resistance is right (and if not, put a resistor in series to increase it or parallel to decrease it).

The valves can go in 4 ways (the end is square, allowing it to be improperly placed at 90, 180, or 270). I found how the pass side went in by shining a flashlight into that side's housing and seeing the hole. Lined it up, then closed it, and tested the driver's side one by seeing if I could blow through a hose connected to the core. Got them both in right now. I am thinking of putting boiling vinegar into the core and letting it sit a bit, then adding boiling water w/baking soda into it, thus cleaning it out well, then flushing it with boiling water and reconnecting it to the engine. But I'll do that AFTER I get O-rings and the washers (if I can FIND THEM )

[psfred]

Coffee pot cleaner containing citric acid will work better -- the citric acid will chelate the calcium more and dissolve more for a given amount. DipIt is the brand name, I think. Probably need three packages or so. Put in very hot, allow to sit, then flush.

Or do the whole engine the MB way (cheaper if you can find some food grade citric acid somewhere -- you need a full kilogram).

I think there are supposed to be four 0-rings in there.

Peter

[Tomguy]

2 O-rings and 2 washers, although I suppose I COULD use O-rings to replace those 2 washers. They're a very odd size, probably very difficult (if not impossible) to find.
I'm thinking of just putting vaseline on the ones I have now and reassembling it, watching it for leaks.

[zambo]

Hi Tom

I did one of my taps recently - the other is a bit stuck and I am working it loose over time by jiggling a sparkplup attached to the threaded tap stem - the fixed one had one biggish O-ring and one smaller one. The smaller one from memory was to prevent any leakage at the tap spindle end of the equation. I have the MB part numbers handy somewhere if you want to compare to yours.

The 2 washers are not on mine - though with the smaller o-ring in place, nothing leaks - again forgive my memory here, but I seem to recall that the smaller o-ring was for an inner diameter opening, not around a shaft as such.

I got the bits needed to rebuild the taps from MB from the only guy I could find at the dealership that could remember how these older heaters worked. He said that the 2 o-rings was all that was needed to sort the taps and of course, some rubber grease (that is 2 O-rings per tap).


Let me know if you need the part numbers for comparison.

Kind regards (and Merry Christmas)

Richard Zammit

[zambo]

Hi again Tom

Sorry for being vague before - being summer here, it is 35C and about 90% humidity and I am so hot it is hard to think!

The smaller o-ring is part no 000 835 48 98 and 11mm in diameter (OD). The seal is an interesting one because if you view it on it's edge it has a slightly concave channel around it's perimeter. This would tie in with my recollection of it being used as an inner seal.

The other bigger seal is approx 17mm in diameter (OD) and part number 000 835 58 08 and is an ordinary type seal with a curved profile looking on it's edge, down the perimeter.

Don't know if this is superfluous info but hopes it helps.

Regards

Richard - currently melting before his very eyes!

[zambo]

Hi Tom

I did one of my taps recently - the other is a bit stuck and I am working it loose over time by jiggling a sparkplup attached to the threaded tap stem - the fixed oner had one biggish O-ring and one smaller one. The smaller one from memory was to prevent any leakage at the tap spindle end of the equation. I have the MB part nunbers handy somewhere if you want to compare to yours.

The 2 washers are not on mine - though
with the smaller o-ring in place, nothing leaks. I got the bits needed to rebuild the taps from MB from the only guy I could find at the dealership that could remember how these olde heaters worked. He said that the 2 o-rings was all that was needed to sort the taps and of course, some rubber grease.


Let me know if you need the part numbers for comparison.

Kind regards (and Merry Christmas)

Richard Zammit

[Tomguy]

Originally posted by zambo
The smaller o-ring is part no 000 835 48 98 and 11mm in diameter (OD). The seal is an interesting one because if you view it on it's edge it has a slightly concave channel around it's perimeter. This would tie in with my recollection of it being used as an inner seal.

That's why I wouldn't call it an O-Ring, and also why I would imagine it being hard-as-hell to find! Thanks for the P/N's, I can wait to get these from the dealer if I must.
It goes INSIDE of the piece that's visible on the RH of the image I attatched - the same piece that the larger O-ring sits outside of. It goes into the center hole and surrounds the shaft for the valve to prevent leakage from the shaft.

[zambo]

That sounds about right Tom - as to an earlier comment made about whether a big O-ring was also used at the left end of the pic, I am not sure about that. If I read the pic correctly, there is a big O-ring up the right end of the tap (just to the left of those two rubber washer thingo's).

If that is so, that stops any leakage into the cabin. Another seal at the "engine end" of the tap would have no effect on leakage, asssuming the right hand end O-ring was doing it's job.

And again, I seem to recall from my little journey into heater tap heaven that I noticed the channel at the left end but it is just part of the machining of the part, nothing more.

As I said, mine works fine with just two of these seals/o-rings in place. The little o-rings/seals shouldn't be too hard to get - about $2-$3 from MB and delivered in 24 hours here in Oz! I have a feeling that those little seals are also used in other applications on other models, hence there availability

Regards

Richard

[Tomguy]

Originally posted by psfred
Coffee pot cleaner containing citric acid will work better -- the citric acid will chelate the calcium more and dissolve more for a given amount. DipIt is the brand name, I think. Probably need three packages or so. Put in very hot, allow to sit, then flush.

Or do the whole engine the MB way (cheaper if you can find some food grade citric acid somewhere -- you need a full kilogram).

I think there are supposed to be four 0-rings in there.

Peter

I forgot to reply to this one before...
The ***** that came out with the valves reminded me of the crud I took out of my sink's trap (less the hair). And I am not going to put Drâno™ into my heater core!

That's why I thought of the vinegar + baking soda - provides turbulance similar to drain cleaners without caustic lye and other core-killing chemicals. It would clean the goop out rather well, I'd think - like having a flush and backflush rapidly mixed inside the core!

[psfred]

If you want to use vinegar, get the white stuff and use it undiluted (it's about 5%).

The reasons for using the citric acid are: much stronger solution available easily and it will chelate rather than just dissovle the calcium, hence remove more.

Keep adding fresh vinegar until it stops fizzing, the flush with clean water until no more crud comes out. Drain, flush complete cooling system, then drain again and fill with correct coolant.

I can't wait to hear how well this works -- my 280 is definitely NOT a warm car this winter!

Peter

Peter

[Litton]

Good thread, I have the same problem with an anemic heater. The citric acid is the good way to go (vineger is citric acid just very dilute) I would wonder about the baking soda though as it would neutralize the acid. Maybe use if as a second flush for that very reason.

I just happen to have a 50lb bag of the citric around here someplace.

Here is a hint if you are in a area where you could have CaSO4 scaling........add a whole bunch of table salt to the mix. Hmmmm, on second thought with the Aluminum heads one might have to be a bit careful, but it does work.

Peter, I believe you said about a kilo of acid? Also, I assume you run the engine up to temp for a bit.

Dick

[kpb]

Can't just lurk throughout this thread. Litton/Dick, if it's so damn warm out there "108 in winter" why do you have a furnace in your garage and/or even know if your heater works??

My heater does NOT work, but I'm still drivin' it!

No harm intended, just have nothing to add of value . BTW, 50Lb. of citric lying about?? whathehell...

[psfred]

LOTSA o lemonade !!

You need to drain and flush cooling system, including the block to get all the coolant out (you don't want to neutralized the citric acid with coolant).

Drain again, then dissolve 1 kg (2.2 lbs) citric acid in a gallon of hot water and pour into cooling system. Top off with water, then operate about half an hour warm -- MB instructions call for using a "forced open" thermostat -- you can get one or use an old one that won't close.

Leave heater valves full open for this treatment.

After half an hour at operating temp, allow to cool and flush two or three times with clean water, then refill with coolant.

Pretty good bet you will have to scrape the crud out of the block drains to get them open.

Vinegar is acetic acid, not citric. Acetic acid will work, but it will evaporate while you run the engine -- you'll smell like a jar of pickles!

Peter