Radiator Question: No leak, no smoke, but level keeps dropping

[unkit]

Hi guys

I've got a weird one for you guys. First of all, i have a gen 3, (Australian), 94 Camry CSI 2.2l 4cyl Auto with 250 000km on the clock.

I recently been noticing something peculiar when i open the hood. I topped up my radiator fluid like 4 weeks ago. Today the radiator hose seemed all squashed up, I opened up the radiator cap, and the hose poped back into shape. I noticed I was able to add about 500ml of fluid to bring the radiator level back up..

Isn't it weird to have to top up the radiator fluid? I have looked, and looked and looked, and can not find any sort of a leak.

I doubt very much i have a leaking head, it drives as smooth as the day i bought it, it NEVER overheats.... well atleast the temprature guage never shows it is above the middle mark... And i know the guage is working, because in the mornings, it is VERY VERY slow to get to the middle mark. Takes like 3km

I have been running the car on LPG, which probably means the engine is running hotter... could this have anything to do with it?

If the water pump was failing slowly, what would be happening? I don't think it has ever been changed, the radiator is relatively new though... and I had a radiator flush, and thermostat changed about 8 months ago.... (cause the needle stuck to cold, and never moved).

Thanks for ur help.

[JvR]

I am running a Camry v6 on LPG. When my car is leaking water it always is the lpg system.
The fastest way is:
go to a garage and ask if they can put the water system unther pressure.
i think it will cost you $60

[ghettosled]

it sounds like your radiator cap is going bad. what is the coolent level in your reservoir? my guess is if there really isnt a hidden leak anywhere, if excess coolent pours into the reservoir, then if the level is too low there is suction to pull some coolent back from the reservoir. if the cap is bad, it might not be able to pull fluid from the reservoir.

another things to consider - when you topped off the coolent the first time, was the engine off and cold? that could explain why you need more coolent. your thermostat would be closed and your heater core blocked off.

[unkit]

Resivor was almost full..... So u think it might be the cap? One of the rubber parts of the cap seperated from the metal housing itself... does that suggest it might be the cause? I thought the cap was just a cap... just sealed the top of the radiator so no air got in?

I'm not sure if the car was warm or cold..... when should i be filling it?

I'll think about getting it pressure tested... $60 seems like a lot of money to spend just for having the cooling system checked... I think I might try the radiator cap thing first.... It looks like i need a new one in any case.... its pretty filthy.

Thank you so much for your replies

[95PimpingCamry]

^ the cap seals the cooling system up to a certain pressure. Once the cooling system reaches a certain temp and pressure, the cap opens and lets excess coolant into the resivour. So if your cap won't hold enough pressure it is letting all the coolant go to the resivour.

[greggf]

I vote for the cap too. The expansion tank works both ways; when the coolant volume/pressure increases, the cap allows coolant to dump into the overflow tank. Conversely, when the radiator/engine is low in coolant, a vacuum is created that allows the radiator to draw coolant from the reservoir. You obviously were generating the vacuum upon cooling (as witnessed by the colapsed hose) - which is normal - but no draw from the reservoir could take place. In general, coolant should be added to the reservoir.

[Kep]

The clue that I am seeing is that your radiator hose was "all squashed up". This plus your comment that the overflow tank was almost full leads me to believe that your overflow return isn't working correctly. Like ghetosled said, probably the radiator cap (its gasket may be plugging the little tube in the radiator neck when it shouldn't be) or it could be the hose to the overflow tank is collapsing or the breather of the overflow tank is plugged up. As far as I know, the coolant system should never be in a state of vacuum where the hose would squish up.

Kep

[unkit]

Thanks Heaps guys. I'll get a radiator cap today, and see if that fixes things.

ankit