Citric Acid Flush started -> now no heat
 

Good evening,

Put the requisite 2.2lbs of citric into my radiator (after properly do-oiling and flushing) and now I have no heat (monovalve wire disconnected - so I would usually be roasting).

What could have changed to cause this?

A little history:
-Earlier today I replaced the radiator (after the neck broke). Filled with plain water and went for a 20 mile test run. No problems and temp sat right at 85-90. Perfect.

-Flushed and dissolved citric into warm water and poured it in the expansion tank. Idled the car and temp began to climb past 100(!). Figured I had some air - burped system (put on incline, remove rad cap, put heat on, rev to 3k, repeat three times) and added more water and the temp stabilized. Heat was fine at this point, not as hot as before, but OK.

-Went for another drive tonight, turned on heat at end of ride and it wasn't there - had been there in the beginning of the ride. Noted my expansion tank water level is low (not visible in tank), will fill tomorrow morning. I had topped it right before that ride.

- no apparent water leaks, no coolant in exhaust. Could my system still be purging out air somehow? Could my heater core be blocked by stuff being removed by the citric?

Many thanks,
dd

The monovalve has a wire mesh/strainer around it. It might be clogged with crud.

and do check monovalve rubber for any small tears, citric acid may have damaged an already weak rubber seal -good luck!

thank for the replies guys - Ill check those things today, somehow. I really dont want to disturb the citric doing its thing.

top off the tank with distilled water, and squeeze the upper hose until all is full of water. keep driving it. don't worry too much about no heat. all will be well when you flush and reverse flush the heater.
it's not TOOO cold in bean country yet is it?

Now I know why they call it a weep hole!
 

Oh its getting cold now...

That was plan this morning. Started the car to go to work (30 degrees, first crank :-) ). Happened to look down at the water pump, and I noticed water leaking from the weep hole. My water pump must be bad, right?. I specifically checked it yesterday too, and it was fine.

Would the busted pump cause no heat, but not be bad enough to cause the engine to overheat?

Un-freaking-believable. This has been a $300 citrus flush so far (I replaced the radiator yesterday). I know these things would have happened soon anyways, but still, it just leaves me dumbfounded. Im doing it all by the book too, its not like Im doing a hasty job or anything.

So it looks like I need to dump out my $15 worth citric acid, replace the pump, and start over. Is this right? Ive only gone 25 miles on the citric...not nearly enough.

On the bright side I will now not have to remove the thermostat housing to replace my short coolant hose!

dd

I lost my water pump during a coolant system flush. I was performing the flush because of a slight overheat problem when the A/C system was on. I suspected the pump but also suspected a clogged radiator. Turns out it was a little of both. Anyway, I replaced the pump for less than $50...but I feel your pain!

15.00 is a bit high for 2.2lbs of acid... citric acid that is... anyway, you should not loose too much if you just pull the water pump. a lot will remain in the block.

Well that's great news that I don't have to pull the block drain entirely and dump out all the citric acid. Ill just bucket my citric acid solution and dump it back in when the time comes.

I have a couple lingering questions though -

1.a) Ive read the water pump bolts tend to break. I will make the special 10mm box wrench as Brian has suggested in threads past. BUT, how can I play all my best cards to make sure they dont snap? Ill PB blast them like heck and use the ground box-end wrench. Should I heat them? Any incantations I could try? I will *not* be happy if this turns into an extraction exercise on top of what has already gone down:)

1.b) Could the flaky (but still functional)water pump cause my no heat condition by itself? Or am I definitely looking at some sort of multi-fault situation? (Clogged monovalve, bad monovalve, bad aux water pump etc)

Thanks as always,
dd

PS My expansion tank seems to fissuring near the pressure cap...sweeeeeet. Fastlane here I come....

I feel your pain, man. I'm almost ready to pull the engine from the parts car I bought to replace the one with the head I cracked doing my citrus flush. Insufficient burping plus impatience turned PM into a major ordeal.
"Zen and the Art of Mercedes Maintenance" "Doh!"

I can only comment on the water pump bolt question that you have...although i suspect that you have a clogged monovalve situation that may clear up upon completion of the flush. In regards to the water pump bolts, you should have no trouble with them if you use PB and take normal care. I ground down my 10mm wrench for the job as well. It is a fairly simple job overall. I would rate it a 5 on a scale of 1-10.

Thanks - Haynes freaked me out at first by saying that I needed to pull the radiator and all of the belts. Now I see it not nearly as bad as I first thought.

Can a problem in my heating system in any way affect my new water pump? Is it common for a citrus flush to push flaky components over the edge like that?

dd

Not a problem, I think the entire job took about an hour and 1/2. I didn't pull the radiator...although it wouldn't have been that difficult. I placed a piece of cardboard in between the fan and the radiator to protect it. The part that took me the longest was removal of the old hardened gasket. It was really baked on and extremely hardened. I am not sure if someone in this forum has a good procedure for hardened gasket removal? I used a razor blade...very carefully.

Cool. It doesn't seem too hard as long as the bolts come off easy...its just the waiting game for the parts. Its now starting to get cold at night here and I dont want my citric solution to freeze or something screwy like that.

Im wondering if I should go to the junkyard an get a new monovolve and aux pump proactively.

dd

They sell a spray gasket remover that soakes the gasket and makes it easy to remove. Just spray and keep it wet for 15 -20 min and it scrapes right off.

On my race car I have to remove the intake many times and don't want to replace the gasket every time. An old trick is to coat the gasket with grease. It helps with positioning and when removing the gasket does not stick and can be resused. Can be used with any paper or cork type gasket.