Finding a coolant leak
 

2002 tip, 80k
Car started dropping coolant right rear. Obvious coolant tank leak and wouldn’t hold vacuum after draining system. Replaced coolant tank, everything went in fine.
After replacement, used my trusty airlift and it just sucks air, no vacuum. Airlift works fine, tested that and good seal at filler neck. I have a hole somewhere and can’t find it. Any usual suspects here from others experiences. Plan on trying smoke to see where I’m drawing air. I’ve heard the burp valve is bad in new ones sometimes, that would be nice.
Thoughts?


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Are you sucking air through the overflow hose by chance?

Talk to me...I hope I’m not forgetting something. I remember just stuffing the airlift in the filler neck and drawing a vacuum, did I plug something and forget?


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No; the Airlift system is just plugged into the tank fill opening and will pull vacuum if the system is closed; if you are not getting vacuum, something is open.

Any chance you are using an aftermarket tank with a built in leak?

Just had same issue. New tank would make vacuum with airlift. Did pressure test. The bleed valve on the new tank was defective and leaking. replaced the valve and then system held pressure/ vacuum.

Just read through and thought of an old thread. Here it is just in case it becomes relevant. http://986forum.com/forums/performance-technical-chat/47325-my-first-question-bleeder-valve.html

gonna check the bleeder valve, it is an aftermarket provided by owner. hoping I dont need parts

not the coolant tank...and hoses all look good, this is a tip, so wondering if there is something on this different from the manuals? where could this leak be...(dont say anywhere, I know that!)

Yep, it isn't the tank, I can plug it up and holds vacuum, and I can't see a bad hose or anything underneath...this is a TIP, so there is coolant running through tranny I think, but the right rear wheel well leaks. struggling on this.

The only things at that location are the tank and its associated hose connections and the Tip cooler and flow controls.

http://986forum.com/forums/uploads01/0021337649666.jpg

Can you fill with plain water, and pressurize it a bit? Leak should be pretty obvious......

-Eric

Better yet, use water with UV dye in it, pressurize and hit the area with a black light....

We replaced the coolant tank, and that was on its way out without questions, the backside was crazed and brittle. So I dont feel bad about that effort.

The airlift vacuum with smoke was the trick, we had it running and watched the smoke draw straight up the side of the tranny.
There is a plastic diaphragm thing on the passenger side of the Tip Tranny, way up top. the inlet nipple for coolant was cracked. Replaced this and it held vacuum, sucked in the coolant and the car is back up and running.
Thanks for all the suggestions, good ones for sure. hopefully this helps another with a mystery leak in the passenger side rear wheel well. Tip cars only!

BTW, JFP...the picture is AWESOME, This helps the next guy for sure since you cannot see this in the car. I missed seeing your post on my earlier responses, but knew about the cooler. In fact, I had the part on a shelf so when we discovered it broken I pulled it down. My friend was left wondering...why did he have that part laying around?..haha

928-574-573-03-M53 partnumber

That is the coolant flow control valve for the Tip oil cooler. Glad you got it sorted.

yep, quick question on the Burp Valve...when I pull vacuum, the tank fills with a little coolant and every 20-30 seconds, the tank bubbles and the vacuum drops about a pound.
Is this the burp valve leaking?
does the vent for this extend down to the bottom of the coolant tank, thus bubbles?
is this what I would see with a leaking burp valve?

If the bubbles continue, you have a leak somewhere. It is not usual for bubbles to come out at first and then tapper off; that is just air coming out of the system. But if the bubbles continue, you have a problem.

Agreed, it is slow, and cycles which is weird. It takes 5 minutes to bleed down but does it every 20 seconds a pound at a time. Can’t find it. Think we need UV dye and black light unless you think of something


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At this juncture, I would drain the vehicle, mix UV dye into the water and refill the system. Then pressurize it to 18 PSIG, turn off the lights, and start looking............

Thank you!
 

Very interesting post, thank you for sharing your experiences!

Learned something new today :cheers:
.

Sorry about this, thought I had picture and already out going to dealer. Found the leak, hairline fracture in cooling flange. It is on the bottom of engine, driver side and has a large hose hooked to it headed up front. Think it is main outlet to radiators. Four bolts. What is that housing called, please.


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