Mysteriously dissappearing coolant...

[ElJefe]

Reading turbocruisers HG thread I came accross this post by MoJ...

Although I haven't had any other symptoms I did notice I'd lost a little coolant over the last year. I don't check it that often but made a mark on the overflow tank with a Sharpie about a year ago. It's down a little when comparing cold to cold. I couldn't find any good reason it should have done that if everything was operating properly --- anyone know?

I figured I would throw this into a new thread since I have also been tracking a slowly falling coolant level using the sharpie method. I've lost around an inch over the last year with no apparent weeping at the head/block interface and nothing obviously leaking from the PHH. Never seen a drop on the ground underneath the truck even after sitting for weeks at times.

Is this normal for 80's or is ANY amount of coolant disappearing cause for concern?? Anyone in the HG club recall if your coolant levels were stable leading up to your blown HG.

Other than the HG and PHH... are there any other likely places to look at??

 

[Darwood]

I wonder how much coolant loss we can attribute to evaporation. As we all know, the coolant overflow tank isn't sealed since it has a tube that is open to the air.

 

[e9999]

1 inch in a year is not much I would venture to guess. I think the level may also vary a bit with outside temperature. Maybe not (yet) time to panic...

 

[ElJefe]

I am wondering the same thing. My only other reference is a BMW that has a totally sealed system... pressure cap on the overflow. That thing never looses a drop. I'm sure that in the LC, everytime the coolant expands and contracts it pushes out damp air and sucks in dry air. I just don't know if that small evap loss over the course of a year should be an inch or a millimeter. If it's not an inch, and I can't find any other culprit, then I may have joined the HG club.

 

[Heffenoche]

Is this normal for 80's or is ANY amount of coolant disappearing cause for concern?? Anyone in the HG club recall if your coolant levels were stable leading up to your blown HG.

As a member of the blown head gasket club the only symptom i had was loss of coolant and some white smoke at start up. I lost about a gallon of coolant over a years time w/ about 10k miles over that period. I varified mine with an oil analysis from Blackstone Labs. If you've driven a fair number of miles over the last year I would look elsewhere for a leak.

If you are like I am and worry about these things do yourself a favor and have the oil analyzed so you know for sure.

 

[ElJefe]

I'd be very surprised if I've driven half that much in the last year.

I mostly ride my mountain bike to work in hopes of delaying my outward growth and avoiding having to do the electric seat mod.

I think I may have done 4-5K in the last year.

 

[MoJ]

Jefe -

As you quoted, I've been in the same boat. It's been nowhere near a gallon as Heffenoche mentions above. For the last 8 months I've only driven the 80 on the weekends.

As far as losing coolant in a open system --- hopefully someone smarter than me will chime in. From what I've read there shouldn't be any measureable loss. I'm just guessing but I'd think the rate of loss due to evaporation would be directly correlated with the amount of water mixed with the coolant. Either way, I've decided to go ahead and have it changed.

I should know the results of my oil analysis tomorrow evening and will post 'em up.

 

[ElJefe]

It seems like the common failure for these engines is coolant passage(s) to combustion chamber. If the oil passages are a closed system and not compromised in a typical failure, would an oil analysis show anything even if the HG was on its way out... just thinking out loud...

 

[patpend2000]

After a long drive next time, open the hood, see if the coolant is leaking out of the plastic end tanks of the radiator. I watched coolant bubble out of mine when hot, but when cold it was dry.

 

[MoJ]

It seems like the common failure for these engines is coolant passage(s) to combustion chamber. If the oil passages are a closed system and not compromised in a typical failure, would an oil analysis show anything even if the HG was on its way out... just thinking out loud...

Dunno. But no more than I know about motors you've convinced me it's a good question.

 

[Rich]

Some of what's in the combustion chamber blows by the rings into the oil.

 

[RavenTai]

an inch in a year? I could atribute that to evaporation.

if your HG actually fails it will be much faster rate.

 

[ToyoLoyal]

I agree with the evaporation theory. Especially in a dry climate, the drier the air, the more evaporation takes place. I notice in the summer especially I have to top off the coolant on a lot more cars. I've always attributed it to evaporation.

Makes sense to me.