Where the hell did that come from?

[Bushbasher]

Ok, I have a little story to tell then we'll get to the question, I'll try to be brief:-

Pulled a trailer to Adelaide a couple of weeks ago and an hour into the trip the car, (AUII wagon in sig. below), suddenly starts randomly downshifting ; sometimes on the slightest of rises in the road, sometimes for no reaon at all except maybe a gust of wind, who knows. Anyway, I thought trans was playing up till I rested my foot on the throttle and while on cruise I could feel it flooring itself slowly till it downshifted even though there was no corresponding acceleration, like it was starving for fuel, but hang on, we're running on LPG. I stop, pop bonnet and check all the lines and converter and solenoid connections etc. but everything looks ok so I put up with it till we got to Adelaide then had a proper look. Couldn't find anything except the coolant was suddenly way down; bugger, must have sprung a leak somewhere says I. Topped up and put up with issue all the way home thinking it must be the converter.
Got home and stripped the converter but it was perfect inside, not even a hint of residue of any kind and the coolant level hadn't moved again either. I'm stumped, hmmmm.
Fast forward a week and the missus is off to work yesterday morning but only gets 2kms before the car dies and won't start. I go and give her my car and get under the bonnet of the wagon and the coolant bottle is empty and the converter is frozen, shirt, says I, there's got to be an intermittent leak somewhere cos this is twice now in 2 weeks. I get the car home on petrol and top it up then use it to run to town and back to see what will happen. Now the temp gauge won't come up properly and hovers around the edge of the cold/normal line. Now I'm thinking either the temp sensor has had a heart attack due to the coolant loss or the thermostat is stuck open. So now I have 2 problems, or is it 3? Coolant loss, fuel flow issue and now a temp problem.
Now we get to the question; I pulled the thermostat after crawling all over and under the engine looking for evidence of a coolant leak and finding nothing, and found this rubber washer jambed in the thermostat holding it open-






- it's about the size of a 20c piece. The break is where the thermostat bit it, but where the hell did it come from!

The engine was changed over about 150k ago as it was cheaper than doing a head swap at the time and the thing hasn't been touched since so if it's not part of the cooling system then it somehow made it's way into the block before or at the time of the change over and has been floating around in there for over 3 years.

I've put the car back together and everything seems to be back to normal but I'll just have to see if there is ongoing coolant loss but my theory is that pulling the trailer must have opened the thermostat enough and made enough flow to pick up the washer and deposit it in the thermostat housing partially blocking the heater pipe inlet thus causing the converter to be on the verge of freezing but not quite and every time the car downshifted and revved it forced enough coolant through the line to keep the converter alive. It also explains the temp gauge but what I can't figure out is how it forced out the coolant as the car never overheated at any time and a 50km drive yesterday showed no coolant loss and no puddles under the car. The missus has taken the wagon to work today with some extra water just in case but if there is no loss in the next week or so I'll go buy some more coolant and flush and refill the system.

So... does anyone recognise that washer and where it might have come from and does anyone have a theory on how it might have caused the coolant loss without overheating the engine noticeably cos I'm at a loss right now. If it caused a blockage that created enough back pressure to force fluid out the overflow then it should be cured but if it's forced the fluid past a gasket or seal somewhere else I'll need to do something about it although I'm buggered if I can find any evidence of fluid loss anywhere.

Cheers
Bushbasher

[paulie0735]

Only thing that comes to mind is the washer under the radiator cap, that could also explain the coolant loss.

[ronwest]

That looks like a garden hose washer to me.

Haven't flushed the system with the hose have you?

[Bushbasher]

Good call there Ron, I think you may be right. Yes I did flush the system when I got the car back after the engine swap but the thing is, that washer would have be from the threaded end of the hose that screws onto the tap not the snap lock end where the nozzle connects and there's no way I would have put the threaded end of the hose into the block, it would have been connected to the tap. None of my various hoses in the last 5 years at least have had female threads at both ends and none of the nozzles I've ever had or used have ever been screw on, always snap lock. I did, and still do have a 1/2" canvas hose that has a male thread on the end but it is/was only ever used as an extension so it has a female snap lock fitting on it to connect a regular hose and if I used it on the day it would have been at the tap end of the hose. This can only mean that sometime in that engines past someone has stuck the wrong end of a hose into it. It could have been floating around in there for years I guess and it decided to dislodge itself now. Funny thing is, that engine has dragged a camper trailer about 4000 km and pulled the very same trailer in pulled the other day, fully loaded and gated, from here to NSW and back a couple of times now and it never missed a beat. I wonder what made the washer move now after all this time?

Now I just need to work out how the coolant got out.

Cheers
Bushbasher

[bingoTE50]

You been running the heater ? Maybe the core is leaking and the water is evaporating . Smell different in the car?

[mik]

the water leak and the rubber thing blocking the thermostat at a similar time may have been coincidence do you think? if you have a pin hole somewhere in the radiator /walsh plug/hose, leaking water pump, it can actually run down /spray onto a hot surface and evaporate while still slowly draining over a period of time, pin holes can actually open up a bit with heat then shrink enough to almost stop it leaking and be very hard to find,
i had a pin hole on the thermo fan side of the radiator, it would`nt leak when it was cold and would take some time to lower the level in the egg crate,
i found it by accident while fitting an oil cooler when i had the fans out, i had a green bird powdery poo like emanation coming from one of the radiator cores,
after closer inspection i found a small coolant stain on the bottom radiator tank where it had run down from the bird poo area(again almost impossible to see with fans in car), i suspect any small amount of tell tale coolant would have been evaporated by the thermo`s in my case, i reckon a radiator pressure test might be helpful.

[mik]

how`d you go bushy, find that leak yet?

[Bushbasher]

Hi Mik, mate, I've got no bludy clue. After topping the system back up, (or so I thought) it emptied the reservoir again in about 60kms but couldn't find a leak. So I topped it up again and it lost about 2L but still I couldn't find anything and now it hasn't lost a drop for the last 3 trips to town (60km each way). The only thing I can think of is it emptied the heater core when it caused the converter to freeze and the missus must have turned the heat on and refilled the core. I can't imagine any other way it can suck up that much coolant without losing any. Now the bludy thing has tried to burn itself to the ground, (see the Headlight loom thread). I'm now waiting for the other shoe to drop, as it were, cos we all know these things come in 3s'. I'll keep you posted.

Cheers
Bushbasher

[GK]

Not sure about the coolant loss, but there's a rubber washer about that size in the thermostat itself isn't there?

GK

[Bushbasher]

Hi GK, no mate, the only washer in the thermostat is the seal that goes around the thermostat itself. I've identified the washer as what Ronwest picked, a garden hose washer. I checked it against another one from a garden hose so that's confirmed. What I'm still trying to figure out is how the washer contributed to the coolant loss in the first place seeing as there is no discernible leak anywhere. That being the case then the only logical conclusion I can come up with so far is it must have been forced out the overflow.

Bushbasher

[POELWYK]

could be boiling the water and it comeing out of the Over flow line ..... put a bottle on the end of the over flow line and see what happens

[Bushbasher]

Originally Posted by POELWYK

could be boiling the water and it coming out of the Over flow line ..... put a bottle on the end of the over flow line and see what happens

Yeah, no, I think you misread the original and subsequent follow up post. It did lose water but now it has stopped since I removed the washer that I found blocking the thermostat. The question now is; how did the washer cause the coolant loss when no apparent overheating occurred.

Bushbasher

[POELWYK]

yeah it was only a gess it could of still come out of it if the Seal is old or bad..... i donno after that

[burnz]

is your pressure cap in good condition?
a weak spring will allow leakage at normal temp.
a leaking cap will draw air and not coolant from the resivour.