l28manzz

I have a 77 280z with the original motor and radiator and recently I recently been having overheating issues. It doesn't overheat at idle though. Its only when I'm driving.

So far I have installed two 12 inch pull through electric cooling fans (run off switch, not thermostat), coolant temperature sensor, and tomorrow I will be replacing the thermostat. I am out of ideas for what to try next and need some help. I find it very odd that it doesn't overheat at idle no matter how long its idling for.

Also would a 160 degree thermostat be better than a 180 degree one? Thanks in advance.

borini63

Plugged Radiator or bad water pump...it's time to pull and clean/replace radiator/water pump!!

l28manzz

Well looks like that is my next weekend project.

Thanks for the reply.

beg3yrs

Be very careful when removing those water pump bolts. If you encounter any kind of unusual resistance, use something like PB Blaster to help those bolts come out without breaking. Sometimes they're beyond help and then you're pulling the timing cover as well.

Get a set of new bolts no matter what.

l28manzz

I will make sure to remember that. And I'll get a new set of bolts also. Thank you.

beg3yrs

Just to give you some visuals ...

Bolts broken when being removed ...


Lead to disassembling the timing cover to get at the stubs still in the block.


Even if you are lucky and your bolts don't break, they'll likely look like the ones in the first photo. Glad you're going to replace them.

l28manzz

Got the water pump out without breaking any bolts!! I replaced it but the overheating issue is still happening but its not as bad. I ordered a radiator and I will be picking it up and installing it tomorrow. When I removed the old radiator, a lot of the fins were bent and prevented air flow as well as lots of debris stuck in it. Also there was an A/C radiator type thing that I removed because my A/C doesn't work anyway. Removing this should give me even more air flow. Hopefully the new radiator fixes it.

beg3yrs

Congrats on no broken bolts. Glad the new water pump gave you some improvement. Fingers crossed the new radiator will take you over the top and give you a motor that runs at the temp it should.

l28manzz

It's fixed!!! The new radiator did the trick! No more overheating! Thank you for all of your help. It is much appreciated!

beg3yrs

Congratulations. Time for a road trip!

borini63

Good for you.