kyjaxskater

iTrader: (3)

i recently finished my rebuild on my fd and i think im haveing a coolant issue, but not sure. before i did the rebuild, i put in an off bran 3 row with dual fans an crack. they left me at a constant runnin temp of about 91 C per my PFC. now i get about the same running temp, but only when at idle. whenever im on the highway, or cruising around town not in traffic it settles about 15-20 degrees higher than the running temp. im only 60 miles out of the rebuild, so i thought that it could be air pockets, but that seems to not be the issue. so, the question is, is this normal? or should i dig into it further? also the temp gauge on the dash doesnt move at all when you get it up to running temp.

adam c

iTrader: (2)

Not normal.

Sgtblue

iTrader: (16)

You installed an off-brand radiator with dual fans and what? More specific info. Not the stock fans with stock fan relays? Mods list?
This is normal. But if it ever does move higher, you might end up needing another rebuild.

kyjaxskater

iTrader: (3)

the fans are hard wired to a swith that i turn on when it gets close to running temp myself. im just concerned about the fluctuating temp on the pfc commander. am i right in assuming that the commander temp runs on a different sensor? there is a delay in the temp change from the dash to the pfc. it has alwasy been this way, so i thought nothing of it. like i said it doesnt get too high, i just cant take it on long road trips. what is the normal air temp that people run on? i was seeing upwards of 50 degrees C. is this too high? could that have something to do with it?

Sgtblue

iTrader: (16)

Yes, the PFC reads temps from a separate sensor from the thermoswitch that (usually) activates the fans. You said the PFC always settles 15 to 20 degrees different the "running temp" when "cruising". What are you referencing? What do you mean "running temp?".

And no, intake temperatures won't have alot of influence on coolant temperatures.

djseven

iTrader: (56)

You installed aftermarket fans? If so put the stock fans back on asap. If working correctly they are more than effecient and about your best option. Does your car have the underbelly pan?

kyjaxskater

iTrader: (3)

my running temp is about 91 when at idle. when i am on the highway or at a constant drive, then my temp on the pfc elevates about 15 degrees. the gauge does reflect about 5 minutes later, but then drops back to where it was at "normally". the pfc doesnt drop, it just stays running at the elevated temp.

i cant install the stock fans, they were broke when i replaced them, and the radiator is too thick. the stock fans would get in the way of the intercooler and battery. i never had issues before when i had these fans installed. the problem only came after the rebuild.

Sgtblue

iTrader: (16)

Again,
*Are you comparing the PFC reading to the stock gauge?
*If not, where is the aftermarket gauge sensor location?
*Do you have the belly pan installed?

arghx

iTrader: (3)

If you suspect the PFC reading is off you can buy a new water thermosensor from Mazdatrix.

rx7rcer09

put stock fans back on as see what happens, while driving your temps should lower not rise also what radiator is it exactly?

kyjaxskater

iTrader: (3)

stock fans wont fit, the rad is too thick. not to mention i dont have them anymore. the car ran fine before the rebuild with this radiator and fan setup. yesterday i was driving it to the store, so no overheat. and i noticed there was some coolant on the ground. i checked it out, and the hose going from the filler neck to the turbos on the top, i want to say inlet, was leaking. when i replaced it, there were remanants of what looked like the inside of the old hose stuck in the hose. could a small clog to the turbos make it only run hot while i am at a constant cruise? im planning on getting the collant system flushed. if anyone has any ideas what would be a good, cheap way to flush it out myself, i would appreciate the info.

kyjaxskater

iTrader: (3)

i would say the wierdest thing about this problem, is that the temp on the dash gauge barely fluctuates at all. even when the pfc starts getting close to the dangerous temperatures, the dash gauge bumps up a little then almost immediately drops back to normal.

hades

iTrader: (4)

the dash gauge is not linear. It has 3 settings - cold - normal - screwed.

Sgtblue

iTrader: (16)

^Yes, as mentioned previously, pay no attention to the stock gauge. It's worthless and the reasons why covered at length throughout this section.

Consider your PFC temps accurate. You need to get something figured out IMO. I suspect that if your seeing 91 C this time of year in Colorado Springs with normal driving, you'll have more serious problems in July or August at that altitude. For reference, my daytime ambient temps have probably been close to yours and I rarely see above 81 C. while moving.

Recommendations have been made. Check the basics...is your t-stat opening fully? Aftermarket fans running as they're suppose to. Ducting and belly pan in place? No air in the system?

kyjaxskater

iTrader: (3)

im pretty sure there isnt any air in the system. i did a bleed on it last week, and it all seemed fine. the fans are hard switched in. i turn them on usually only a couple miles down the road. i havent checked the t-stat yet, and the ducting is in place. im not sure what you mean by belly pan, but i would assume since the car was running fine with this same setup before it shouldnt be an issue. ill just go ahead and replace the t-stat and see where that puts me.

Sgtblue

iTrader: (16)

Not my picture, but this is the "belly pay" or "undertray". If you don't have one, get one and install it. Without it, you won't get enough airflow through your radiator.


And I think your getting hung up on "it worked before, why not now" mentality.

NissanConvert

iTrader: (1)

The undertray makes an enormous difference in engine cooling and iats. I doubted this myself until I picked one up at aspec while having them lower my fan temps.

Since I've put it on the only time my fans come on is after I park the car and let it heat soak. My koyo practically overcools my car at speed.

If there's debris in your water lines you need to get that sorted, there's no telling where that gunk could end up.

Recently after reassembling my cooling system and trying to troubleshoot a coolant leak I found it at my ast. Make sure that all of your hoses are tight, warm the car up, get some gloves and check for leaks. My leak wasn't detectable with the car cold.

kyjaxskater

iTrader: (3)

ok i have never had that before. ill take your work and start looking for one. do you think a coolant flush will push the debris out of the turbo coolant lines?

DaveW

It depends on the debris. If it is just soft soluble gunk, then a flush may work. If it is anything more substantial, then you may need to pull them off and physically check and clean them.

Why do you think the turbo coolant lines are plugged? That will not affect the overall cooling, it would just overheat the turbos, and there is nothing there to measure the actual turbo temperature. The problem sounds to me like a lack of overall cooling capacity at speed or higher output (lack of bellypan, clogged radiator, bad thermostat, etc.).

DaveW

To expand a bit on what I said above, the fans will keep the coolant temperature where it should be at idle, or low speed, low load, city driving. However, at high loads or high speeds, they (either stock fans or the ones you have) cannot provide enough air-flow through the radiator to control coolant temperature. Air forced through the radiator from the inlet at the front of the car does that. That is why the things everyone has mentioned, especially the undertray, are important.

Dave

kyjaxskater

iTrader: (3)

i found some hose debris in the inlet line when i replace the hose. it isnt that big, i would assume it would flush through. i also have a potential belly pan on the way. ill go pick up a thermostat this weekend and see how it goes.

Sgtblue

iTrader: (16)

I think having no under-tray/belly-pan is your problem. But the new T-stat is inexpensive, relatively easy to install and still a good idea.