Thread: Replacing Thermostat?

Engine runs at good temperature for about 5 minutes then temperature goes to the max. when i shut er down the fluid is bubbling and the rad is cold. Is my thermostat the problem? I should be able to replace it myself, right? i just need a new thermostat and some sealant?


I have a repair manual but it doesn't show me were the housing is.
I take it this is it:

210 Water Pump, Cooling Fan & Thermostat :: Exhaust & Cooling :: Genuine Nissan Parts :: Sentra / NX Parts (B13) 1991-1994 :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com

Should be a 30 min job and would be a good idea to start there.. Drain coolant, disconnect right water hose from the thermostat housing. Remove 3 10mm bolts on t-stat housing. Remove t-stat housing & remove old T-stat. Clean both surfaces of housing until clean & shiny (I use a razor & fine sand paper). Install new T-stat w/ breather hole on top. Apply silicone on one of the surfaces (1/4 bead but not too much) and re-install housing. Re-install bolts but do not tighten all the way. Let cure for 10-15 mins and torque 10mm bolts to the correct specification.. Re-attach everything, fill up with coolant, start car and follow the "burping" procedures.

thanks, how many litres does it hold, will a couple of 4 litre milk jugs do the job

More than likely it's your water pump. But while you're at it, you might as well replace both items. The water pump is a hell of a job though. All i'm saying is don't expect it to be one and not the other.

PS: Make sure to use high temperature silicone meant for cars ^_^.. permatex RTV works good.

mmm, one thing i didnt point out is that the fluid is pretty dirty. WATER PUMP THEORY SOUNDS LOGICAL, would it cut out after five minutes. I got the permatex gasket sealant. WHY IS CHANGING WATER PUMP HARD?

Sounds like a possible head gasket issue.

Sounds like a rod knock. Just pull the whole engine.
Dude just do the thermostat, and properly bleed the cooling system. If you still have problems let us know

The clearance between the rail and the motor is pretty tight, so its hard to get to the bolts you need to get to, and its hard to clean the surface of the motor to put the gasket goo on etc.

As above, do the thermostat and go from there. I'd put pulling the water pump with the motor still in the car pretty much at the top of the "do not want" list of jobs.

lol @ squa...
When you see oil in the coolant, then it's a headgasket issue...... probably.

If the fluid hasn't been changed in 5+ years, yes... that stuff will look rusty and brown and crappy. Could be overdue for a flush.

As for the water pump, yes it's a huge pain in the ass. I have heard mention of unbolting the motor from the motor mounts and holding it with a cherry picker for more clearance. It's that tight in that area.

You can try replacing the thermostat first, but it's unlikely that's the problem. If you have the money, time, and skill you ought to do both at once to avoid the pain in the ass of dumping tons of coolant out of your car and bleeding it all over again.

While Nissan was very generous with the displacement on this car, they seem to have not considered that you'd actually need room to replace accessories... :|

honestly sounds like a thermostat problem to me. Water pump is possible, sure, but you'd be better off replacing the t-stat, testing it in boiling water, and seeing how the car runs with a new. If it is the thermostat, problem solved. If it isn't, now it's time for the big undertaking. "Wasting coolant" is a bad reason to do the water pump if you don't have to.