V36 VQ35HR thermostat install - Warning!!!
#1
V36 VQ35HR thermostat install - Warning!!!
It's starting to get cold here in Missouri and my check engine light just came on. So I run the code and it relates to the thermostat not working correctly, I also noticed that the gauge was lower than it was in the summertime. Well a few days later it was 12 degrees in the morning and the coolant temp gauge would only go up two bars which means just enough heat to defrost the windshield and take the chill off. (Thank God for heated seats) So this weekend I decided to install a Gates 33912 replacement that cost just under $20 shipped. I pulled my driver side air box / MAF tube and also the cam cover so I would have room to see. Next I pulled the lower radiator hose and drained the coolant, then removed the 3x 10mm thermostat housing bolts and removed it. The factory thermostat has a rubber type seal around the plunger, it was distorted and falling apart holding the thermostat open so it wouldn't get to full temp as it got colder outside. The new thermostat is built like the old classic type metal to metal. As I installed the replacement thermostat I reused the MLS type factory metal gasket instead of the paper type that came with the replacement. I put the 3x 10mm bolts in and when they bottomed the thermostat was still loose??? So I pulled it back out and measured everything to see why the factory bolts wouldn't work. Well the new thermostat housing is thinner than stock so you end up with 6mm + too long of bolts. If I were to torque them down not paying attention it would have stripped them out and or broke the aluminum on the head side. So I measured the bolts and used a angle grinder to cut them down and then used a belt sander to round the tips so the threads would go in smooth. I tested the bolts with a 10mm nut before using them in the aluminum so I wouldn't damage any threads.
I thought I would put this install warning out there so this doesn't happen to anyone else. Here is a link to another user here that bought a car with the exact problem and they destroyed the mount holes in the head trying to install a thermostat:
https://g35driver.com/forums/g35-sed...ing-issue.html
Replacement thermostat
Cut down bolt
New vs Old
Original length
Length on new housing = too long
New vs Old
New thermostat
Old housing - Damaged rubber seal is the problem
Removed cam cover for clearance
I thought I would put this install warning out there so this doesn't happen to anyone else. Here is a link to another user here that bought a car with the exact problem and they destroyed the mount holes in the head trying to install a thermostat:
https://g35driver.com/forums/g35-sed...ing-issue.html
Replacement thermostat
Cut down bolt
New vs Old
Original length
Length on new housing = too long
New vs Old
New thermostat
Old housing - Damaged rubber seal is the problem
Removed cam cover for clearance
Last edited by scumbagsleeper; 11-18-2019 at 01:37 PM.
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This is a warning about any aftermarket thermostat. They should be visually checked and measured before install. The one I installed was a Gates 33912. The factory PN# 21200JK20A will fit fine but will probably fail again because of the stupid rubber seal on the plunger. The aftermarket thermostats are not built like that.
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Yeah but even aftermarket components are dimensionally the same.
@scumbagsleeper I'm curious to see if the bolts you pulled off the engine are actually the correct 11916-JK23A bolts for the HR motor or if somehow it was assembled with (or previous mechanic replaced with) the 11916-31U0B bolts from the DE motor.
I know those HR thermostat bolts are SUPPOSED to be shorter than the DE bolts and I could have sworn they were a full-thread bolt and didn't have a shoulder on them like the bolt you took a picture of. I'm not aware of any thermostat housing revision for the HR but I've never actually LOOKED before. Possibly Nissan switched housings sometime during production and the later revisions actually were thinner flanged?
@scumbagsleeper I'm curious to see if the bolts you pulled off the engine are actually the correct 11916-JK23A bolts for the HR motor or if somehow it was assembled with (or previous mechanic replaced with) the 11916-31U0B bolts from the DE motor.
I know those HR thermostat bolts are SUPPOSED to be shorter than the DE bolts and I could have sworn they were a full-thread bolt and didn't have a shoulder on them like the bolt you took a picture of. I'm not aware of any thermostat housing revision for the HR but I've never actually LOOKED before. Possibly Nissan switched housings sometime during production and the later revisions actually were thinner flanged?
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