Overheating 70-80mph
#1
Overheating 70-80mph
Car runs normal under those speeds. Once I reach 70-80 the temp rises, holds for about 5 minutes, then goes back down for a while. Rinse, repeat. Fluid levels are topped and I'm almost certain there's no bubbles in the system. Things to consider:
-Turbo'd obviously
-Stock thermostat
-no belly underpan
Any ideas?
-Turbo'd obviously
-Stock thermostat
-no belly underpan
Any ideas?
#2
Elite Member
iTrader: (21)
Join Date: Jun 2006
Location: Point Pleasant, NJ
Posts: 2,957
Total Cats: 2
you should make sure air coming through the mouth has to go through the ic and radiator. IOW block off the sides and bottom and make sure you have the rad cowl cover in place so air can't just go around like it wants to. Johndoe did a really nice setup, search for that.
I've noticed that at around 70 i see my highest CLT's. has to do with air just building up at the nose, miata sucks aerodynamically . same RPM in 4th gear at the same load sees much lower temps
I've noticed that at around 70 i see my highest CLT's. has to do with air just building up at the nose, miata sucks aerodynamically . same RPM in 4th gear at the same load sees much lower temps
#3
My 99' did something similar. Overheated when the A/C was on and going +75mph. Kinda like you say. On and off. It would overheat, then "catch" itself. That is, the thermostat finally opened up all the way. Anyway stock old thermostat wasn't opening all the way. New mazda thermostat and that was the end of that.
And I'd suggest you put the belly pan undertray thingy back on. And 70/30 water/antifreeze. Hell, your in FL, 110% water/ -10% antifreeze.
And I'd suggest you put the belly pan undertray thingy back on. And 70/30 water/antifreeze. Hell, your in FL, 110% water/ -10% antifreeze.
#6
IMO a lower temp thermostat is a BAD idea. The engine is designed to run at a certain temperature. It's machined such that when operating at normal temperature, exacting clearances are kept to minimize wear. If the operating temperature of the engine is reduced, the clearances are increased. This causes accelerated wear which just adds to the problem.
Little example: Dad was a shrimper for 27 years. He's rebuilt and helped rebuild MANY diesel engines. It's well known that once an engine starts to wear out, they go fast. Most engines would last 3-4 years of good service, and then over a short period of time (say 400 hours of use), the engines oil consumption would double. Power drops, engine oil pressure would decrease, etc. End of the season you'd have to overhaul the engine.
Awe hell, my example's going nowhere. It'd take forever to develop into something meaningful. Point is you run a motor colder than it should it will wear out really fast. Racing they use lower temp thermostats because a loose motor makes more power AT THE EXPENSE OF EXCESSIVE WEAR. Also running the engine cooler gives you more of a 'cushion' for the cooling system as when you boost you can boost longer before you overheat. Nother reason it's popular. But the fact remains it's bad on the engine.
Ideally you'll have a cooling system that can maintain the correct temperature ALL the time whether at idle, cruise, or boost.
Little example: Dad was a shrimper for 27 years. He's rebuilt and helped rebuild MANY diesel engines. It's well known that once an engine starts to wear out, they go fast. Most engines would last 3-4 years of good service, and then over a short period of time (say 400 hours of use), the engines oil consumption would double. Power drops, engine oil pressure would decrease, etc. End of the season you'd have to overhaul the engine.
Awe hell, my example's going nowhere. It'd take forever to develop into something meaningful. Point is you run a motor colder than it should it will wear out really fast. Racing they use lower temp thermostats because a loose motor makes more power AT THE EXPENSE OF EXCESSIVE WEAR. Also running the engine cooler gives you more of a 'cushion' for the cooling system as when you boost you can boost longer before you overheat. Nother reason it's popular. But the fact remains it's bad on the engine.
Ideally you'll have a cooling system that can maintain the correct temperature ALL the time whether at idle, cruise, or boost.
#7
now that it's getting a bit cooler I'm worried that my cooling is a little too effective as well. During the day when it's 70F+ I maintain normal operating temps but last night while tuning, even after my 16th full boost (14psi) run on the highway in a row my CLT temps would quickly drop to 170F when I let off and cruised for a minute.
#20
Car runs normal under those speeds. Once I reach 70-80 the temp rises, holds for about 5 minutes, then goes back down for a while. Rinse, repeat. Fluid levels are topped and I'm almost certain there's no bubbles in the system. Things to consider:
-Turbo'd obviously
-Stock thermostat
-no belly underpan
Any ideas?
-Turbo'd obviously
-Stock thermostat
-no belly underpan
Any ideas?
Stephanie