So after a search of the knowledge base here and not luck, here is my predicament.

I have an 88 Samurai, no mods that has started loosing coolant.  The problem is I can't tell where it is going.  I have checked the oil, no water.  I even changed my oil to make sure.  No white smoke out the exhaust.  No performance changes. No water coming out of the weepholes in the water pump.  It just seems to be disappearing.  And, it is disappearing at a rate that I would expect to see something somewhere to tell me where it is going.

I am at a loss and appreciate any ideas you guys have to keep my DD on the road.

One thing I forgot to mention, the temp guage reads very cool when driving and will warm up a bit when idling, and then cool back down right away.

Sounds like your truck doesn't have a thermostat installed, other than
that, you might look at the cooling tube behind the water pump, they
get rusted out, and sometimes the O-ring starts to leak, but if that checks
out OK, you might see about getting a test to check for combustion gases
in the coolant, you may have a blown head gasket, but still not get any
coolant in the oil.

The exhaust can pressurize the cooling system and push coolant out the
overflow, which brings me to another point, have you checked the cap???

Wild

Thanks Wild,

I replaced the cap today, and will see what happens.  The overflow tank is empty and I refilled it when I replaced the cap.  I will have to set aside a weekend to tear into the pump to check on that tube.

Where would I get the coolant tested for combustion gasses?  We don't have emissions testing centers in Iowa because we don't have any emissions regs.

You won't need to take the pump off, the tube is behind the
alternator, just get down there and take a look at it while idling
and see if it's dripping any

Sweet!  I thought it was going to be a pain to check on that.  Do I need to take the pump off to change the oring or tube?

No, it comes off from the back of the pump, there is 1x10mm
bolt that holds it in place, and there are the heater hose and
a small line that connects to the intake manifold, the O-ring slips
off the end and replace it with the new one, a light film of silicone
on the tube under the O-ring and in the hole in the block where
it slops in to prevent leaks.

Wild

Thanks for the tip Wild!  You saved me a bunch of work!

Also the lower radiator hose attaches to it, I almost forgot about that one

also; top off radiator and with the cap off watch the coolant. it should flow smoothly with out bubbles (once system is purged). if you have constant bubbles or water is pushing up and out the fill hole you probably have head gasket issues. I just went through this with my nightmare diesel conversion.

Just wondering if this disappearing act could also be a bad heater core ??

Yes it can - the coolant drips onto the carpet and may go completely unnoticed - in my case, I was wondering what the greenish gook on the carpet under the dash was - and then I figured it out.

usually a strong antifreeze odor will be present though.

Just wondering if this disappearing act could also be a bad heater core ??

No smell or wet carpet so I don't think it is that.

also; top off radiator and with the cap off watch the coolant. it should flow smoothly with out bubbles (once system is purged). if you have constant bubbles or water is pushing up and out the fill hole you probably have head gasket issues. I just went through this with my nightmare diesel conversion.

If there is air in the system, will the coolant level rise as the air moves through the system?  Or will it just bubble?  Is there a purge procedure?

Quote from: Jluck on March 10, 2011, 02:40:22 PM

also; top off radiator and with the cap off watch the coolant. it should flow smoothly with out bubbles (once system is purged). if you have constant bubbles or water is pushing up and out the fill hole you probably have head gasket issues. I just went through this with my nightmare diesel conversion.

If there is air in the system, will the coolant level rise as the air moves through the system?  Or will it just bubble?  Is there a purge procedure?

yes the coolant will rise and bubble for a while but should go away. if the bubbles are constant I would do a leak down test.