[Brian]

i decided to do a coolant flush last weekend and replace my thermostat. simple job, right?

all was going well until i realized that the car i bought in the spring had no thermostat!!! yep, i pulled the hose off the water pump and there was nothing but space in there. so i've ordered in the various seals and rings that secure it in place, plus a vanagon fan switch.

in the meantime, i noticed that my coolant tank is really dirty. looks like hard water deposits (i really don't know what it is, just what it looks like). i took the tank out of the car and flushed it with tap water like crazy this morning. even flushed it with some vinegar (what you'd use for a humidifier in a house). it looks better, but still pretty nasty.

so my question for the experts is this: how important is it that the tank is clean? is there anything i can use to clean out the junk? i just can't get a toothbrush in there to scrub. i guess i could order a new tank, but then it's another week of waiting.

advice would be appreciated.

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[Greimann]

If it is free of loose crud then technically it should work fine. If the looks bother you, then some more aggressive cleaners. For hardwater stains, try something acidic like CLR. A good strong mix. Maybe even a bathtub soap scum remover too.



Rinse it well and then try some alkaline cleaners, like Super Clean.



Just don't use lacquer thinner or acetone, they will attack the plastic.

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[968gene]

had no thermostat!!!

You need to ask yourself why was it removed. You may have cooling issues ahead of you when you replace the thermostat. Sounds like you may also have those deposits in other passages in the cooling system (radiator?)

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[Brian]

IF I HAVE DEPOSITS ELSEWHERE IN THE SYSTEM, IS THERE SOME PRODUCT TO FLUSH OUT THE WHOLE SYSTEM?

THIS IS MY FIRST TIME FLUSHING A CAR, SO I'M REALLY A NOVICE HERE (OR A ROOKIE!).

WOULD IT MAKE SENSE TO FLUSH EVERYTHING WITH SOME KIND OF SOLVENT LIKE CLR, OR WOULD THAT DESTROY THE SYSTEM? DO THEY MAKE SOMETHING IN PARTICULAR FOR FLUSHING COOLANT SYSTEMS?



THANKS FOR ANY HELP.

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[968gene]

There are a few products on the market that will remove the scale and deposits, but beware, you might induce a few leaks along the way if you use chemicals to scrub the system. I mild flush may be in order, but something aggressive may ruin your weekend! I understand that the old Jag SJ6 shop manual would recommend a can of Stop Leak after a flush (along with the new coolant). I know that last sentence will breed a few responses...but you may want to have a can handy if the system starts to leak after a flush.

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[flash]

think of it this way - anything in the tank will end up in the system sooner or later - you can get a bottle brush from almost anywhere to get in there and scrub it



i still can't believe the no thermostat thing - it stunned me when we were on the phone at the time you found out - very weird



gene - i've used that stuff before on standard radiators, but never on an aluminum one or one with plastic tanks - no clue how that might work out

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[968gene]

flash, if by that stuff you mean Stop Leak, the Brits were dumping it into new cars before they left the factory (I'm told) and I think those radiators were aluminum.

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[Brian]

coolant system update...

first, i drained the system (for a couple days waiting for parts) and used an air compressor (thanks flash for the tip) to really push out every last drop of old nasty coolant. the article from clarks garage for a 944 flush says that there's a drain bolt on the engine block, i couldn't find it and i don't think it exists on our 968's. then, my coolant tank was so dirty that i couldn't even see through it, so i removed it and soaked it in clr for a couple hours (thanks for the tip, greimann!). i scrubbed as much as i could with toothbrush and bottle brush (couldn't reach very far!). the tank looked much better. i ran water through it for five minutes or so to get as much clr out of it as i could. next, i installed a new vanagon fan switch and a new napa heater control valve (thanks, bruce for the tip). you need a very small hose clamp for the vacuum hose to stay on the nipple because the napa nipple is smaller than the oem. then i cleaned out all the piping with a touch of clr and rinsed thoroughly with water. after that, i removed radiator all the way and sprayed with a garden hose from both sides. lots of junk came out of that. next, i reinstalled all pipes and parts. had to get some new hose clamps since the originals were one-time-only users.

i got some powder from napa for flushing the coolant system. you dillute it in a gallon of water and run it along with whatever other water you need to fill up the coolant system for a half hour at idle with the heater on full blast. with the steam coming out of the radiator for the first 15 minutes, i'm guessing that the system was full of all kinds of crap. (the thermometer in the pressure tester never went over 110 F so i know it wasn't overheating). drained that stuff out of the radiator, ran about a half gallon through the system to flush that out and refilled with new water.

i failed to mention that i borrowed a pressure tester and made sure to bleed the system through the top vent with every fill. i also pressurized the system to 10psi for about 15 minutes to make sure that there were no leaks. the system held perfectly before and after the flush, thank goodness!

i don't have thermostat parts yet (thanks dealership!!!) so i'm just running water for now. the car definitely idles more smoothly and seems to run a little cleaner. i havent' seen the coolant temp gauge go over the 800 position yet. the fans do kick on at 800 when i'm idling, so i know they work.

a couple observations for any other rookies out there....

the coolant plug in the radiator will break very easily. it's some sort of plastic. i broke my off while reinserting it. it came out very easily with an easy-out. however, i replaced it with a stainless bolt (painted blue, of course!) and then stripped the threads in my radiator. i think this was more due to all the debris that drained out of the system than to the bolt because the bolt was not even in all the way when it stripped. i did manage to get the stainless bolt to seal the system with a small o-ring on it. however, i think i'm going to look for an expandable grommet tonight to use long term. should work like a boat plug. i don't want to have to worry about stripping that thing anymore.

also, the coolant will tend to drip out of the radiator when you drain the system and run along the bottom metal rail. this creates a real mess. as i found out, coolant will eat garage floor paint. it's very easy to take a cutting disk on a dremmel tool and cut away a small corner of the rail so that coolant will just gravity fall to a drain pan no matter how slow it is trickling. i'd highly recommend this. if you were handy, you could even epoxy a little dam on the rail just past your cut to make sure that coolant never flowed up that rail.

i'm supposed to get my last thermostat o-ring in tonight. i'll install the thermostat and hopefully get everything back where it should be.

nothing is easy!!!

thanks everyone for the tips along the way

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