Mystery of Missing Coolant

[joesho_gb]

Started a few weeks ago, when the weather here in Wisconsin started getting cold.
I'm loosing coolant at the rate of about a gallon every 500 - 700 miles.
I have parked the car in the garage on top of clean cardboard after running it for a while, checking to see if I can find any spots on it after being parked all night.
Other than behind the wheels and the sides of the front bumper from driving on snow or sleet covered roads, the cardboard is clean (mainly from the radiator to the back of the motor). I don't see any oil, coolant, or any type of engine fluids on the cardboard.
When it's running, it's still dry. A look under the hood, running or not, engine warm or cold, I can't see anything dripping or leaking.
Any suggestions on where I might start?

 

[ycode90]

o-ring seals on the coolant tube that goes from waterpump to T-stat housing.

 

[elarm1]

You can get the motor pressure tested to find the leak. You can also put a black light or black light pen to pin-point leaks. Any sign of it burning it?

 

[Eastcoast SHO]

i would pressure test it first, coolant system can be fustrating. if you test it first you will save yourself alot of hassle and alot of money. just my 2 cents

 

[joesho_gb]

o-ring seals on the coolant tube that goes from waterpump to T-stat housing.

Where is that located? With all the tinkering I have done with my SHO so far, I'm pretty good with the trans sdie and middle of the motor, but the area's around the belt and cooling area, not so sure.

You can get the motor pressure tested to find the leak. You can also put a black light or black light pen to pin-point leaks. Any sign of it burning it?

I can't see any signs of it burning it. The exhaust smells normal, not like a sweet smell, and I don't get any of the smells through the heating system like coolant burning. (it did smell very rich for a while, then cleaned the O2 sensors, and that went away)
With the black lite / pen, would I just follow all the cooling lines and find the spot that glows?

 

[joesho_gb]

And how do you do a pressure test? What tool(s) do I need?
Thanks again!

 

[ycode90]

Parts store will rent you a pressure test kit. The tube runs from the back of the Waterpump between the heads to the rear of the t-stat housing . It's all most impossible to see with the intake on.

 

[elarm1]

Where is that located? With all the tinkering I have done with my SHO so far, I'm pretty good with the trans sdie and middle of the motor, but the area's around the belt and cooling area, not so sure.


I can't see any signs of it burning it. The exhaust smells normal, not like a sweet smell, and I don't get any of the smells through the heating system like coolant burning. (it did smell very rich for a while, then cleaned the O2 sensors, and that went away)
With the black lite / pen, would I just follow all the cooling lines and find the spot that glows?

Yup you got it!

 

[SHOmethewayhome]

the O rings are in a metal tube that runs along the valley of the motor between the heads, from the passenger side of block (waterpump) to the driver's side (where the thermostat is) there is one O ring on each side of the tube.

i'll bet if it's leaking it'll be one of those two little bastards. ask me how i know... go ahead.

 

[joesho_gb]

ti'll bet if it's leaking it'll be one of those two little bastards. ask me how i know... go ahead.

Guessing it happened too you.

I'm assuming then I have to take the intake off? Like stated in previous post?

If so, Goodie goodie. Been almost 2 months since I took the intake off. I thought my knuckles looked a little too clean and not cut up, now I remember why LOL! :woo-hoo:

Ok, if the intake's gotta come apart, then the tools come out tomorrow and away we go! Gives me a damn good excuse to go buy a new torque wrench and test the valve cover bolt tightness.

Any auto parts store has the rings I assume? :thankyou:

 

[TopGunnYFZ]

How weird my gf's car started to do the same thing. Only one time did it leave a puddle and it was behind the passenger side tire. I checked all over for leaks but dont see anything. Theres nothing even coolant related over there and its not the heater core, i may check those O-ring on the water pump side.

 

[LJRuddy]

I'm interested to hear your results. Both of my SHOs have this problem but it is only in the winter. A month and a half ago, my gen 3's low coolant light popped on and I let it go for a week until I finally filled it back up. Only took a 1/3 gallon to top it off. My gen 2 looses about a gallon of coolant every month during the winter time. As soon as ambient temps go above 40, I can go the rest of the warm period without adding any coolant. No drips or smells detected and pressure test passed in July and in December.

Good luck!

 

[SHO Continental]

My brother's SHO had this problem, it was leaking from both the water pump and the water pump side of the crossover tube mentioned above. FYI, you don't need to take off the intake to replace it, but you do need to take off either the waterpump or the two-piece housing behind the thermostat. I'd recommend the two-piece housing if you're not replacing the waterpump at the same time.

 

[joesho_gb]

I drove mine since October (when I bought it), and this just started happening once the temp stayed below freezing. Weirdest damn thing, I tell ya!
I'll look for those O rings this week.
I'm now dealing with another gremlin that just popped up, charging system. AAGH!

 

[rubydist]

The other place I've had them leak with the same symptoms was the upper radiator hose at the thermostat housing - if it has a small leak there, it will also pool on top of the motor and evaporate before the engine cools, just like if the crossover pipe o-rings leak. Make absolutely certain that the clamp is tight on the thermostat housing.

 

[joesho_gb]

I don't see any indication of coolant on the engine block at all. No odd stains, no smoke, no smells. I'm going to check all of it though. My SHO must be scared of the cold weather or something. Between this, my trans going direct to 2nd gear when I put into drive (which was fixed by pulling the batt cable) and now a charging problem, all within 3 days, can't help to think that my SHO was born on the west coast or something LOL

 

[ycode90]

Gotta love SHOwnership.

 

[SHOtimer]

My SHO used to do this. I discovered the the endtanks of the radiator leaked coolant untill it heated up enough to expand the seal and stop the leak. So, the whole time I was driving while the motor heated up it was leaking out the radiator....

New radiator fixed it.

Doug

 

[smokin joe]

I wouldn't do the O-Rings until you know 100% that its leaking from there, I have had this issue twice with my sho once it got cold enought in past years, and both times it was some part of the lines that go to the heater core, also as said check every coolant connection and make sure all the clamps are tight and not leaking. Find the problem before you start replacing things hoping it fixes the issue

 

[joesho_gb]

When I climbed under the car this morning to check the battery cables going into the starter, I did notice a bit of coolant on the hose going into the bottom of the radiator, on the passenger side.
Also, there is a really small radiator mounted just a bit off center (to the drivers side), has 2 rubber lines hooking in through the top, and a metal tube shaped like a U on the bottom. I noticed a small amount of coolant on that as well. What is that little one?