So I am loosing a lot of coolant, no leaks anywhere.  No huge amounts of white smoke either.  Where is it all going?

 

 

A lot can get sucked down the intake without smoke.

 

A fair amount can leak on top of the block, and dissappear. Look for evidence.

 

The right kind of pinhole in the radiator and a cap that doesn't hold pressure is another sneaky one.

Make sure it isn't being pushed out the overflow tank, which indicates blown headgaskets

I find my leaks by putting in UV dye. It makes finding leaks very simple and effective as it leaves a trail all the way to the leak. $15 can save tons of time and even money in the end

All these are great suggestions...  ^^^

 

I would say change your oil, and look at the separation in the pan after a day.

 

Antifreeze can go into the oil and emulsify, it doesn't always go into the combustion chamber

-or- check your oil stick and look for ugly mayonnaise. 

 

Consider the following:

Pressure can move from the cylinder to the coolant system, and this can be checked with a bubble chem test at the radiator. It's exhaust going into the coolant.

Pressure can move from the coolant system to the cylinder and this will significant white smoke once the engine is warmed up.

Pressure can move from the coolant system to the oil and make oil/anit-freeze mix emulsification

Pressure can move from the coolant system to the atmosphere in the form of a leak.

 

Pick your favorite.

I have had 3 places coolant goes:

 

1.) on top of the block, collecting in the wells of the passenger side spark plugs

2.) a little burning up I can see in the exhaust, also no huge amounts of white smoke (none of that ugly mayo thank goodness)

3.) a tiny pinhole leak in my radiator, driver's side, near one of the large hoses.  It doesn't always leak, usually only while driving. When it does, it goes directly on to the road while moving

 

Good luck!

A lot can get sucked down the intake without smoke.

 

A fair amount can leak on top of the block, and dissappear. Look for evidence.

 

The right kind of pinhole in the radiator and a cap that doesn't hold pressure is another sneaky one.

 

 

The evidence I saw was a sort of dry, white, chalky, almost salt-like residue under one of the hoses on top of the block, which almost immediately evaporates because of engine heat.

Edited November 7, 20178 yr by Tony Cortado

My coolant was disappearing too. No white smoke but when I pulled the carb the base gasket was shot allowing coolant into the intake manifold. Also discovered 3 hose ends with white crusty stuff on them indicating leakage. Also discovered the previous owner installed a 13psi radiator cap and I was losing heaps of coolant out the overflow. A new 15psi cap sorted that. I also replaced the water pump for piece of mind while I was under the hood. Hasn't leaked a drop since.

Ps. I pulled the spark plugs first fearing the worst (blown head gasket) but thankfully they all looked fine. Good luck in your search for the culprit!!

No evidence of water in the oil.  I do have some white smoke on start up but it quickly clears up.  I think I'm just going to keep adding coolant until the leak is so bad it becomes obvious (or I have to do something about it).  I'm thinking a bad gasket somewhere causing an internal leak.

 

what is the lowest ratio of anti-freeze to water mix I can get away with to make it through the winter.  I'm thinking 3/4 water to 1/4 antifreeze, or can I go lower?

Water in the oil is not common. I only saw it once and that was due to the worst overheat while low on coolant that I ever had. Very blown headgaskets. But it still ran great.

 

If you continue to run it with the unknown leak, check the coolant very frequently. Like before every start. You do not want to have air in the system to the point where it goes over normal temperature. I've seen a slow leak turn into a headgasket blowing overheat in one 20 minute drive.

IIRC there is a small 90 degree coolant line under the intake manifold that you should check. mine was split causing lots of coolant to spill out on top of the block but i didn't find it for a while.

there are a total of 7 cooling system hoses on an EA82.  Check all of them.

Sealwel it

Update:  So the last 3 times I checked the radiator and overflow canister, no loss.  fluid at correct level.   ??????

 

So either some gnomes repaired my car at night......OR........a piece of crud(???) has lodged into the internal leak , blocking the leak?

 

Again I am stumped?

Keep a close watch on it.

My 90 lost a significant amount after running down the interstate then has stayed fine since topping off. However, has the car overheated at any point? I have seen a curious loss of coolant which come to find out was a small crack in the head between valves allowing coolant to be burnt without actually leaking.

In my forinstance,  2 times I have had intake manifold gaskets crap out.  Luckily,  they leaked to the outside of the manifold, it would of been just as easy for it to do it to the inside of the manifold without any signs of leaks besides the radiator going low.  I will never use FelPro intake gaskets again,  a little harder to find, but I will allways use OEM gaskets there.