RotaryBuddha

iTrader: (4)

ok for those that havent read my other thread https://www.rx7club.com/2nd-generation-specific-1986-1992-17/intersting-cooling-problem-580630/
please dont post in their if you have a comment then post it in here.

ive been going back and fourth working one thing out and it working for a little bit then it start up again. well this time i think i have got it figured out.

so tested my oem thermostat in a pot of water to see at what temperature it opens at. 190 it opened. which from what i have read is fine for stock. also the reason i tested it is because i have been noticing that my upper radiator hose has been swelling.

ok so will doing some highway tuning with the microtech i decided to try and re-create my problem and observe the microtech temp readings.

while cruising at normal road speeds 45-60. my engine temp stays at 88 C or 190.4 F
which is fine.

when im under heavy load or high speed cruising 80mph the temp will rise to 94 C or 201.2 F. now this is getting on the dangerous side. i held it at 80 for about 5 minutes and it didnt go past this mark. but this was at night. in the middle of hot florida day my car would be toast.


so i guess what im trying to get at is. that my thermostat isnt opening soon enough so the water in block gets hot but when it gets to rad it cools down too much and it wont open the thermostat so the hose swells up. and if i turn on the heater the water has some where else to flow to. and the engine temp drops but the hose is still swelled.

now what im wondering is if i were to get another thermostat with a lower heat rating say 170. would i still see my upper radiator hose swelling because the thermostat isnt opening until 190.

also i have taking temps from the radiator and they were in low 180s. their was no cold and hot spots.


sorry for long winded post

RotaryBuddha

iTrader: (4)

no comments?

Mushy B

umm.... so what you're saying is that your thermostat is opening at 190 in a boiling pot of water.... then there's no reason for it to not be opening while it's in the car, there's not really any environmental differeces except using water with anti freeze and having pressure in the system. Your thermostat should be opening just the same, if not easier with pressure to help it along. But perhaps it sticks or isn't functioning properly. You could replace the thermostat, but i'm assuming you already have since this has been an going problem. The next thing to go after that is a restriction in the system or poor pressure from the water pump. If your radiator has no hot spots then that should be good to go. Try flushing it anyways just as a precaution if you haven't already. Also i'm assuming your not losing radiator fluid due to a broken seal in the engine. Other than that i could only focus on if your engine is running too lean/ too hot, and therefore it's causing some overheating conditions. Goodluck with your cooling issues, and keep us posted!

RotaryBuddha

iTrader: (4)

if anything i have too much pressure on the system right now. ive had hoses split on me. im not loosing any fluid. coolant seals are fine no smoke or smell whats so ever. all this stuff has been covered in my other thread.

im running 50/50 coolant. could that be a problem as well.