[Robs64ss]

I have a 07 murano overheating. Wife drove it too far and warpped the heads. Machine shop performed new head work ,new radiator, new water pump, two new thermostats. Had air pocket then got it bled out didn't overheat for three month in winter. Then started to climb decided to go to Nissan and they said cross over pipes leaking so changed wasn't gasket in it from machine shop just RVT gasket sealer. After swap still over heats oh about 1 mile with AC on. Then they said it wasn't a Nissan thermostat I let them change again was Nissan one so they didn't charge me for that. By the way there was nothing wrong with the crossover pipe ether. 600.00 + you can buy gasket for around 2.00 bucks. Then they suggested checking catalytic converter's imagine the bolts being rusted. I told him to hold off. Went back to original machine shop and he pulled heads and sent them in again read done I had them tested OK. Check water pump and timing assembly new put it all back together tried another thermostat test drove the car BAM overheats again with Ac on. Fans have been tested exhaust in the radiator fluid been tested everything pressure tested. No one wants to look at my car and less they keep just throwing parts at it someone please help would catalytic converter's plugged up make it overheat . The car run 70 miles an hour down the highway without hesitation gas mileage is 16 to 17 MPG. One of the catalytic converter's is black on the lower half temperatures are about 140° difference in to going out. NEED HELP

 

[Pilgrim]

There are these things called paragraphs...they make it easier to read and understand your posts.

I don't understand all your post, but the first thing to do when you're having problems with a Murano is to have the fault codes read. That's where to start.

I think you are having overheating problems only with the AC on, correct? No problem with the AC off, correct? Let's start there.

As far as cats, the rear one can be replaced with a generic unit. The front ones under each exhaust manifold are available online at lower then local dealer prices.

 

[koltonv]

Yep.. let me get this straight,, does not heat up after heads are done, then heats up a little bit so you take it to the shop, and then it heats up a lot.

I wonder if you have air in the system again. .... follow my logic,

Does not heat up, for 3 months, then starts to go up, the shop says you have a leak on the cross pipe, they fix.. and then major problems again. if the leak caused a little air in the system this would cause your temp to starts to spike. Then when the crossover pipe was changed you got air in the system again.

Try and burp your cooling system, and see if that fixes your problem.

Good Luck.

 

[Pilgrim]

Good idea. There are sometimes problems with getting the air out of the system, and that could be at least part of the problem.