95 maxima no heat

What does the engine temp guage say?

If it's running cold, you may have bad seals on the 'stat, which allows the not-hot-enough coolant to be cooled by the radiator, thus no engine heat, thus no heat for the cabin.

If the engine temp is normal, your thermostat is probably fine.

If the engine is running hot, either the 'stat is not opening (unlikely), or your water pump isn't moving the coolant enough to cool the engine. Thermostat failure is usually the seals going bad, not failure to open.

In any of these cases, you may also have a blocked heater core. I'm guessing this is the problem.

I used to live in Oregon, and did a lot of snowshoeing in the mountains, especially Mt. Hood. I'd park at around 6,000 feet. When I would drive home, my car would never heat up on the way down the mountain (no heat, no defrost!). It would finally heat up when I got down to flatter terrain when the engine had to work a little harder. I had a bad thermostat (worn seal). It was never allowing the engine to heat up properly. Replaced it and had heat all the time.

Bill G '91 SE Auto

I'm having the same type of problem...and I also know that my waterpump is about to go out. So, I'm guessing it's that.

I'll replace the pump and see if the heat comes back. (/me crosses fingers.)

Matt

Make sure you replace the engine temp sensor (located above the thermostat housing) and the thermostat. Bleed the air from the system through the little cap screw near the heater hose fitting. Also, make sure the vacuum operated water valve is functioning properly and that there are no breaks in the vacuum line.

Chris

See Chris H.'s post first.

First, do NOT buy a remanufactured pump, buy one from a Nissan dealer. The price difference isn't that much, but my re-manned unit went out after about

Second, make sure you replace the timing belt and t-belt tensioner while you're in there. I don't care if you just changed them 5,000 miles ago, do it again! The parts are cheap, and you will have already done 90% of the work to get to the water pump, so do the belt too. And, if you get any coolant on the t-belt, it can wear out much faster.

Third, you WILL need a torque wrench for this job. Do not attempt it without one. The water pump and thermostat housing use a liquid gasket, and must be tightened properly. In theory, you only have to wait an hour or so for the liquid gasket to set. But if you can wait 24 hours, all the better. This only pertains to filling the coolant and running the engine. Feel free to re-assemble immediately. (Although I have found that right after installing the water pump and thermo housing is a perfect time to sit down and drink a few beers.)

Take your time on this repair, it's a necessary one every 60-90,000 miles.

If you want to go a step further, you can remove the cam sprockets and the rear timing belt cover to check for leaks from your cam shaft seals. One of mine was leaking, and it was fairly easy to replace (and cheap). Gave me a chance to clean the engine behind the rear belt cover too. The easiest way to remove the sprockets is with the old timing belt in place. It will provide some tension, and keep the cams and crank shaft aligned, while you loosen the sprocket bolts. Make sure the engine is still Top Dead Center after you loosen, then pull the belt and sprockets. The sprockets are keyed, so you can't put them on incorrectly. Just make sure you don't mix up front and rear. Use the old t-belt again when you re-install them.

If you do this, you can torque the front cam sprocket with a wrench, but the rear one is very difficult to get a torque wrench on. Per NissTech, use the German method, make it Gudenteit.

And one last tidbit, save up some swear words to use when trying to remove and later re-install the upper and lower timing belt covers. You will be convinced they came from another car.

Good luck. Many of us have done this repair more than once, so feel free to ask questions.

Oh, and skip all this if the last sentence also refers to you.

Bill G '91 SE Auto