Monsterbox

iTrader: (6)

Dropped my car off at a local rotary mechanic for fuel filter change and discussed my heatsoaking issue

- car is hard to keep under 200F even with the fans running full time and heat on full blast

-car drops in temps only when cruising above 55mph, radiator is ducted, all hoses replaced, and new thermostat in car, koyo radiator

- sitting at idle in 82-96+ heat, the car climbs slowly...but its been getting progressively worse over the past month or two to the point where I have to have the heat on all the time

I originally thought I needed a vented hood because my I/C duct is so large that It could be restricting the fans' airflow.



----Rotary mechanic thinks that its a bad waterpump or a corroded water pump housing or both causing the water to flow too slowly hence why it only cools down with MAX airflow on the interstate.....what do you guys think? what exactly are the symptoms of a bad pump? I know when I remove the TB hose to burp system, I can definately see water being pumped out! Its not like its sitting still

DaveW

Well, he could be right, but it sounds to me more like an air flow issue, as you originally thought. If the WP were bad, cooling would not improve just due to more air-flow - it might get worse at higher speeds since more coolant flow is also required to handle the increased heat output.

Are the fans running properly?

What happens if you are sitting still with the fans on and you increase the revs to a constant 2500 or so? If it is a WP problem, the temps should go down due to increased water flow.

Are you running aftermarket pulleys that reduce the WP speed? It's not running backwards, is it?

IRPerformance

iTrader: (41)

Oem or aftermarket thermostat? Installed with the correct orientation?
What coolant to water mix are you running? try 70% distilled water and 30% coolant.
The pump will usually leak out of the weep hole when bad.

Monsterbox

iTrader: (6)

thankyou for the reply

i think its an airflow issue due to the big SMIC and big SMIC metal duct blocking the radiator.

Stock pulleys, removed airpump


yep no weeping at all, 80/20 mix

IRPerformance

iTrader: (41)

What intercooler? Although they do block some air, I have never seen it become an issue. The stock setup is the same way. Pick up an air pump removal pulley kit such as greddy or one of the copies sold by the rx7 store, gotham racing, or other vendors. The water pump will not have enough belt contact otherwise and will slip. Keep the stock main pulley. In my opinion the regular koyo is pretty crappy, but still shouldn't cause an issue. Are you sure the fans are comming on and hitting high speed?

Monsterbox

iTrader: (6)

im absolutely positive the fans are coming on and flowing the correct direction...it will suck up paper underneith the car against the condensor and radiator

My undercover is damaged in the back but this should not matter at idle

Koyo can't possibly be worse than the stock radiator and shouldnt matter at idle

Belt only slips when I get water on the pulley....

Its the "shitty ebay" pfs knock off intercooler but I have a HUGE aluminum custom duct in front of it thats greats REALLY hot in front of the I/C and blocks one of the fans....however I have relocated the battery and you can actually see half the radiator and fan on the right side...im just so confused as too why the temps climb

I did have a fan that was malfunctioning a month or two ago so I replaced both fans with 35k mileage fans...maybe these "new" fans just blow?

As soon as I hit the freeway the temps drop like a rock! but sitting at mcdonalds waiting on food the car almost overheats I have a fan mod switch allowing me to turn them on whenever I want too!

Mahjik

iTrader: (1)

Actually it can. The fact that the Koyo is larger, which means it will have a heck of a lot more hot coolant running through it without any air moving across it (while idling that is). Once the fans kick on, they will not be as efficient pulling air through as they were designed for the stock radiator which is 2x thinner. So, in essence the Koyo can possibly be worse than the stock radiator in some cases and it does matter at idle (as that's the worse for a running car since there is no airflow).

Monsterbox

iTrader: (6)

good point, but why when I bought the car exactly 12 months ago, was it IMPOSSIBLE to run over 185F with fans on in any heat condition? I had stock i/c and plastic intake however

so how do I test the WP? Rev it to 2500 see if the temps stablize?

Solution:

Larger fans from Summit Racing?

or

Get vents installed into my hood and retain stock fans?

or

Both needed?


BTW Im very suprised that this is not a common issue

DaveW

And may have a denser fin pattern, enabling it to transfer more heat with less airflow...

Here's a related situation: https://www.rx7club.com/showthread.p...=radiatorworld

Mahjik

iTrader: (1)

I've seen many people incur slightly higher idle temps with the larger radiators over the years. Most people end up switching from a stock radiator which has had fins beat on for years. Replacing a radiator with beat up fins to one without will show an improvement in itself. Thats what most people generally end up seeing the performance benefit from, straight fins again.

However, I don't believe that is necessarily your problem. IMO, I don't think you have a problem. If you couldn't keep the car under 230F, then that would be a problem. However the car running 200-210F is not a problem.

Monsterbox

iTrader: (6)

well maybe im a just a whimp!

its never seen over 225F in the year that i've owned it...its just I remember keeping it at 185F all the time and now in the summer is climbs so fast to 200F that im terrified to keep driving It seems like the rate that it climbs too 200F will be the same accleration up to 225+ if ignored?

So you expect it to level off at 200-210F at idle if I leave it alone?

this really increases chances of detonation tho

xurotaryrocket

the ECU doesn't even kick the fans on until over 220F. It's good to be cautious, but I think you're just a bit paranoid.

When I originally put that radiator in... it was much better at cooling while driving at speed, but around town/idling temps suffered slightly. The "problem" is probably being compounded by your large IC/duct and boost levels.

Again, does not seem to be a problem.... ESPECIALLY considering that you're in ALABAMA!!!

Monsterbox

iTrader: (6)

ryan,
I found out the problem, one of the fan relay wire was not plugged into the actual connectors...I must have somehow unplugged it installing my primary turbo intake. This has caused my fans to constantly run at low speed. I plugged in the wire and the fans actually blow air into my face!!!

Car runs perfect and maintains below 200F at all times...only problem is now I have some sort of electrical malfunction causing the meter fuse to blow, sent it to the shop

alexdimen

iTrader: (13)

I wouldn't trust a mechanic that attributes a cooling problem to the water pump. A mechanical pump either leaks, has bad/noisy bearings, or works perfectly... there is nothing else that can go wrong.

MrNizzles

iTrader: (5)

Good point, but how many Rotary mechanics out there? Maybe a good suggestion would be to have the guy read these forums as well?