CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Nissan Murano 2003 leaked coolant rusty pipe.. . .stalled . . . .fixed pipe, .now what? please help

Hello. I wrote in yesterday, so i might have a repeat here, but it is not appearing yet.
My Nissan Murano, 2003 is acting up after a ton of diagnostics and repair . We replaced thermostat, flushed heat core, replaced coolant pipe which had rusted and leaked out fluid, and ran air bubbles out forever, it seemed. The heater does not work now on lower rpm’s and the car was gurgling the other day when i stopped at mailbox. I have been driving it for a few weeks since we had it repaired.
When i pulled in into garage, it was overflowing at reservoir for coolant. We have not driven it and our mechanic is perplexed. He ruled out head gasket problems with chemical test and another diagnostic test. . . .he is perplexed. He added coolant and what else. . … .that is all i can think of . should we get it towed to dealer which is 100 miles away? we’ve already spent 1500 or so with this and it seems we could be back at square one. Our mechanic is very honest, and he does think it could be in the engine, like a warped plastic piece. . . i don’t know what he said exactly, but he’s just guessing.
We have 128k on this engine. Thanks a lot

Have your mechanic pressure test the radiator cap. If the radiator cap is weak and can’t hold the proper pressure coolant will be forced into the coolant reservior.

To remove any air from the cooling system, get the engine up to operating temperature. With the engine idling, loosen the upper radiator hose clamp and slip a small flat bladded screwdriver between the radiator hose and and the hose neck on the radiator. Allow the engine to continue to idle until all the air is purged from the cooling system and nothing but coolant comes out. Remove the screwdriver and retighten the hose clamp. Once the engine cools back down check the coolant level in the reservior.

Tester

thanks so much for your comment, Tester, I will ask my mechanic if he will do that. He says the tests revealed no head gasket issue… .so we are hoping for minimal cost this time!!

i guess the cap is new per our mechanic. a couple weeks old . . . . . .STILL WONDERING WHAT CAN BE WRONG?

Wanted to mention that the car will not warm up (heater , that is) in idle. The idle was truned up by our mechanic, and heater worked better, but another facility turned idle back down when CHECK ENGINE light appeared lit and i took it in to be sure. THANKS AGAIN

Check the overflow reservoir. There is either a tube that hangs down from the cap or a tube molded in the side of the reservoir. If the tube is the hanging type, it should be there, check for cracks or loose fit. If it is the molded type, check for cracks and check where it opens into the tank that therre isn’t some sort of debris acting like a one way valve.

From you description, it sound like coolant is getting into the overflow reservoir as it heats up and expands, but is not being drawn back into the radiator when you shut the engine down and the coolant cools and contracts. A defective radiator cap can cause this and even a new cap can be defective. Even a cap that holds pressure can be the cause if the outer seal is not good, the cap will hold pressure but not vacuum. Could even be a defect in the neck of the radiator.

Have him test the new radiator cap. I’ve gotten brand new radiator caps that were defective.

Tester

Thanks, Tester. You rock. I will forward this to our mechanic and maybe he can try another new cap. I don’t know how one is sure about the vacuum ability of the cap, and if it has a look when purchased, but i appreciate your help. i also will ask about debris:>)

I’ll add to the good advice already given only this tip: when flushing air out of the cooling system, the heater has to be on. There’s a valve in the coolant hose going to the hearet core that needs to be energized to allow coolant to flow into and the air to escape from the core. Turning the heating system ON energizes that valve.

You use one of these http://www.amazon.com/Stant-12270-Cooling-System-Pressure/dp/B0002SRGWU/ref=sr_1_1?ie=UTF8&qid=1363021611&sr=8-1&keywords=stant+radiator+pressure+tester to determine if the radiator cap holds the proper pressure.

Tester

There is no test for the vacuum portion that I know of, but if you look at the bottom side of the radiator cap, there are two rubber seals. There is the disk at the very bottom of the spring portion and another seal on the underside of the top of the cap. The bottom seal holds the specified pressure, the upper seal holds vacuum. Mostly, you just inspect the upper seal looking for nicks, cracks cuts, etc. Also check the mating surface on the neck of the radiator, that is the top surface or lip.

Many great points. Thanks to all of you!!! I will talk again to our mechanic and keep updated. I appreciate your help here!