Hi guys,

Have some 'overheat' issues (seeing pretty high water temps on my Haltech). I never let it go to high to be damaging.

I would love some pointers where to spend monies on to get this rock solid, love the car but not liking this temperature problem!

I'm a Celsius guy so it'll all be in that.

Background:
I've upgraded the tiny rad with a 50mm core rad and two 10" highflow fans, I had to do without the shroud since it wouldn't fit , this is hooked up to the OEM fan wiring (operation of this is a bit strange, explained later on*...) I'm using a oil cooler mounted up front to the one side (covering a little bit of the IC). It's a build engine with very few miles on it (Uprev 06 engine), not using the exhaust timing (fully retarded at the moment, looking for plugs so I can hook this into the haltech). Using OEM thermostat. I'm using OEM front bumper with no additional holes made for airflow. I'm currently running without under tray with a Zspeed tray to go on.

What I've seen on track is the following:

wheel speed and boost doesn't really matter but the temp climbs from normal operating temperature to a few plateaus like 85c, 90c, 95c, 100c < I stop driving here...

Intake temp was no more then 35c (max), ambient temp was around 6-8c. (so cold enough outside!)

I'm currently not monitoring OIL temps (almost ready to go in though)

I had an issue with a burst coolant pipe on track so when I fixed this and later bleed the system (3 times) I went back on track and monitored temps again, same behavior so thought I must have got all air out of the system, but not sure if it's a culprit or not. I've since filled 1l of water (day after trackday) I took the car out yesterday for some further monitoring normal cruising at motorway speeds and see a constant of 84c (no fans on...) after some slower spirited driving (more boost) it goes up to 87c-89c, I then stopped the car and it went to 93c almost in an instant.

*Fan operation, I've hooked the fans in to the OEM wiring, found some post on here on how to do it. I have seen the 1 fan coming on with AC turned on and both fans coming on at 94-96c! (nothing before that) So I was guessing that one of the relays was smoked, the 'low' speed relay. Yesterday before taking her out I swapped the high speed relay with the low speed relay. 1 fan is now not coming on with AC on and low speed fans (not sure when this is supposed to start?) not coming on either. Didn't wait for the coolant temp to reach 96c.

Q: What is normal for temps with TT?


could these be problems?

Thermostat not opening fully? (it's obviously working since I can bleed the system and the rad gets hot0
Under tray not installed, supposedly helps forcing air onto the rad.
I don't have enough airflow through my bumper to rad,ic,engine?
fans not working as designed? (I know I dont have a shrowd so wont be getting the full benefit of the fans...think at least one realy is bust)
need a coolant re-circulation system?
I was thinking on getting one of the below to release pressure after hard driving


What should I do?!

 

On my APS TT the fans will come on at 94.5C and then go down to 91.1c before they turn off. This will happen a few times while it's idle and that is normal.

I had a Mishimoto Thermostat on my car which open at 62c and my temps would not go above that once I was on the road. The car did not like this so I switched back to a OEM thermostat that opens at 76.5c. Since switching to the OEM thermostat the car has been happy and I do not see my temps pass the middle mark. I have yet to road test how the temps are on the road but if the Mishimoto temp was any indication it should not pass 76.5c.

Have you inspected your motor for any coolant leaks?
Have you checked to see if your lower radiator hose is getting hot? if not then that is a indication of the thermostat not opening and air still in the system

The reason I asked this is because I had overheating issues and found that one of the drain bolts on the block was not sealing correctly and would leak a little under pressure and introduce air in to the system. I took it out and put some gasket sealant on the thread and no problems there after.

The fans seemed to have been working as intended until you swapped those relays I would swap them back to their original configuration. I would also try to put a shroud on it since you are saying you do not have much air flow from the front bumper

 

^ agree. Air in system or thermostat or fan issue. Having only one fan come to simulate stock low speed operation on is suboptimal. It's better to have both fans come on at 1/2 speed using a PWM controller. If you want to keep it to a simple relay, just have both fans come on at high speed if either the low speed or high speed stock fan trigger is activated. My car sounds like a jet plane with both fans at high speed, so I like having a PWM controller.

 

What a strange post. It's as if you understand some things well, and others not at all.
Let's start with the rad cap. That is just a locking rad cap and if you "release pressure after hard driving" you're going to need another car to get to the burn unit at the hospital. Do NOT do that.
Although I don't have temp logs handy, your temps don't sound as "yikes" as you think. (Not hugely valid, but my motorcycle fan doesn't come on until high 90's in Celsius.)
First of all, are you using coolant, or just water? Do you realize that the boiling point is higher in a pressurized (your cooling) system than it would be on a stove? With a proper mix of coolant, it won't boil until about 130°C and you are nowhere near that. Plus, I doubt you would get there once your fans are fighting it.
Put your undertray on to eliminate a variable and look into getting a shroud as well, but overall, I think you might not have a problem at all.
DO NOT TAKE THE RAD CAP OFF TO RELEASE PRESSURE AFTER HARD DRIVING.

 

How do you monitor your temp range? The OEM gauge is very poor in showing what's going on with temperatures. (until it's a tad late...)

I had a leak previously rear of the engine but that has been fixed a good while back, I'll check again (when it's not rained for a few days...) not loosing coolant though so would be a very slight leak if any, do you think that's enough? to cause air to enter?) I'll swap the relays back later on today before I go for another test. The radiator lower hose is getting hot so the thermostat is opening, just wondered if it could be something wrong so it only opens halfway or something. Thanks for the input.

 

Might just use the AUX connector on the haltech to control these fans rather then using a the OEM fan control module.

 

Hmm are you sure you know what those caps are used for?
Lever System Allows Hot Vapour To Be Released Safety Without Scalding User.
• Designed In A Lemon Type Shape Provides Compact Design Plus A Facility To Grip
• Facility To Handle High Pressure Situations


I think that with my current mixture of coolant/water it'll be somewhere of 125c before boiling but I rather not get to that level I'm really posting to see firstly if people running boost applications see these temps after a very short time of driving and what I can do to fight it. I'll get the zpseed undertray on for sure.

 

I use a HKS Camp 2 to monitor my temps.
The leak can be slight and not enough to be seen on the ground.
Yes it can cause air to be introduced when the system depressurizes.

 

Ok so you would get accurate reading from the ecu itself? Sounds like a needle in a haystack to find a leak if there is any there

 

id also like to interject that you add the pathfinder rear coolant bypass kit thats very cheap (199 bucks) the next time you have the engine out.

Ive added one to my buildas its hot as hell here anyways.

But youve had some good replies.

Your issue lies in the answers you had been given so far, but if youd like more cooling, the pathfinder kit and an undertray as well as nose air diffuser piece up top will help.

and no.. dont touch the cap when its even kind of warm.
Silly.

 

Lol ok no cap think engine needs to come out soon enough anyway so might look at that pathfinder cooling upgrade. Does it actually make a huge difference?

 

looks like it could be a few things, IMO.

I'd look into a different way to control the fans(haltech, or other unit). And make sure the fans do in fact flow enough CFM to actually cool that radiator. check voltage at the fans to make sure they have the power they need also.

It might also be a head gasket/head lift issue, where PSI while in boost is getting air into your cooling system. I know it's a built engine, but many people have had this problem after builds.

Also, what are your AFRs running too lean can cause a spike in temperatures also.

my .02 cents

 

I think Haltech is the way to go it's there ready to control this, so agreed there.

So fans able to cool the fan you are talking about hit the fans and watch the temp at idle, cruising, boosting? Would there not be other problems with lifting head/gaskets? I'm not yet monitoring AFR, have the bits just not the time to stick it in there. (I really don't think I've got a tuning problem though, the guy that did the tune is solid, unless something has changed with the setup since I had the tune...)

What does anyone thinks about the fully retarted exhaust timings? I drove it again yesterday to and from the airport with a few full WOT runs and no problem with heat increase. After I stopped I could hear a wiss noise from the rad cap (high pressure). I think I also found at least one leak! The APS valve that does away with the OEM bleed valve doesn't seem to be tight enough, could see small coolant leaks and hear air escaping. Still trying to find this leak free funnel system that you can get in the states, seems nobody bothered bringing that stuff into europe...

Cheers
A.

 

Forgot to mention,

Did you try a new radiator cap? I had a lot of coolant blowing into my reservoir, and swapped the cap to one from a 300zx tt, and that fixed that.

it might not be holding pressure anymore.

 

Its brand new with the rad, might try the hks one i got or the oem one

 

sounds silly but do you run water wetter? May help mate? Heat wrap in the engine bay to help? My varies bonnet helped coolant temps too

 

read some troublesome things about that wetter stuff so not sure I want to use it in there

Might have to go fin bonnet even though I don't want to Think the start will be to wait for this funnel thing and get the new lower coolant hose replaced, trying to source the pathfinder mod parts too. what temps do you get on your APS build? (our builds pretty similar...)