Jump to content
SAU Community

Recommended Posts

Hi,

My car has recently begun to overheat.

Initially the first instance presented as very high oil temperature reaching 110 degrees.

a couple of minutes later, after passing 110 mark I noticed the water temperature begin to rise above half way.

Once I reached home I noticed the overflow full of coolant. Mind you it was old coolant.

So after changing the thermostat, coolant, and radiator cap I tested its stability under load.

and sure enough the oil temperature does still reach 110 eventually.

Originally I thought this might just be due to thrashing around abit.

So I decided to go for a run on the freeway. 100 kmh for 30 minutes.

Sure enough the temperature reach 110 again, but water steady.

My questions are, and I apologise for my ignorance.

1) Is the oil heating the water? or is the water heating the oil?

2) if the oil is heating the water, why is it reaching such a high temperature?

3) if the water is heating the oil, what could be causing this?

Thanks

Link to comment
https://www.sau.com.au/forums/topic/461511-high-oil-temp-r34-gtt/
Share on other sites

Hi, My car has recently begun to overheat. Initially the first instance presented as very high oil temperature reaching 110 degrees. a couple of minutes later, after passing 110 mark I noticed the water temperature begin to rise above half way. Once I reached home I noticed the overflow full of coolant. Mind you it was old coolant. So after changing the thermostat, coolant, and radiator cap I tested its stability under load. and sure enough the oil temperature does still reach 110 eventually. Originally I thought this might just be due to thrashing around abit. So I decided to go for a run on the freeway. 100 kmh for 30 minutes. Sure enough the temperature reach 110 again, but water steady. My questions are, and I apologise for my ignorance. 1) Is the oil heating the water? or is the water heating the oil? 2) if the oil is heating the water, why is it reaching such a high temperature? 3) if the water is heating the oil, what could be causing this? Thanks

there's a factory heat exchanger which keeps the water and oil temp inline.. benefits of this.. cools down the oil when it gets too hot and also brings oil temperature to operating temps

Draw backs, if the oil temp exceeds the water temp, it will bring the water temp up. A way around this is to increase your cooling capacity by installing a decent radiator which should theoretically keep the water temps in check and also keep the oil temps a little lower.. but real world says you need to also install an oil cooler to bring the overall temperature of both oil and water down.

People often look for highly technical reasons for overheating..

My first thought always is to take the radiator (or the whole car if you are so inclined) to a radiator repair shop. They will take the top tank off and clean out the core, replace the top tank if necessary (many are plastic) and tell you if a recore is indicated. They can flush the block and replace the thermostat.

If you haven't done this in recent history it is worth doing anyway and will very often fix your problem.

The oil heat exchanger serves 2 purposes.

Firstly it helps get the oil up to temp quicker by pulling heat of of the water and transferring it into the oil and secondly it works the other way around by transfering heat from the oil back into the water once the oils too hot.

Ideally the oil and water temps should be at the same temp as the factory thermostat.

Now if your water temp is good but your oil is getting too hot, there's something wrong if your just cruzing.

Start by checking the oil temp sender and wiring (and possibly gauge).

A bad connection may be causing too much resistance which may explain the high temp readings.

  • Like 1

Due to the water/oil heat exchanger I'd say you are just seeing your water temp reflected on the oil temp gauge.

On my R33 with a blocked radiator the factory water temperature gauge sat at half way from 70C all the way up to 105C - it never budged. Only when you head up north towards 110C the water temp gauge starts to show it getting "a bit warm" - IMO 105C is already way too warm!! (was checking actual WT values using Consult tool).

Blocked radiator, blocked/faulty thermostat, or bad water pump.

As a point of reference my R34 GTT handled continuous abuse on the track and the highest I think I saw was 103C on the water. You should not be reaching that sort of temperature on the street.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • I got back to Japan in January and was keen to get back on track as quickly as possible. Europe is god-awful for track accessibility (by comparison), so I picked up a first-gen GT86 in December just to have something I could jump into right away. The Skyline came over in a container this time and landed in early January. It was a bit battered after Europe, though—I refused to do anything beyond essential upkeep while it was over there. The clutch master cylinder gave out, and so did the power steering. I didn’t even bother changing the oil; it was the same stuff that went in just before I left Japan the first time. Naughty. Power steering parts would’ve cost double with shipping and taxes, so knowing I’d be heading back to Japan, I just postponed it and powered through the arm workout. It took a solid three months to get the car back on the road. Registration was a nightmare this time around. There were a bunch of BS fees to navigate, and sourcing parts was a headache. I needed stock seats for shaken, mistakenly blew 34k JPY on some ENR34 seats—which, of course, didn’t fit—then ended up having the car’s technical sheet amended to register it as a two-seater with the Brides. Then there’s the GT86. Amazing car. Does everything I want it to do. Parts are cheap, easy to find, and I don’t care what anyone says—it’s super rewarding to drive. I’ve done a few basic mods: diff ratio, coilovers, discs, pads, seat, etc. It already had a new exhaust manifold and the 180kph limiter removed, so I assume it’s running some kind of map. I’ve just been thrashing it at the track non-stop—mostly Fuji Speedway now, since I need something with higher speed after all that autobahn time. The wheels on the R34 always pissed me off—too big, and it was a nightmare getting tires to fit properly under the arches. So I threw in the towel and bought something that fits better. Looks way cleaner too (at least to me)—less hotboy, less attention-seeking. Still an R34, though. Now for future plans. There are a few things still outstanding with the car. First up, the rear subframe needs an overhaul—that’s priority one. Next, I need to figure out an engine rebuild plan. No timeline yet, but I want to keep it economical—not cutting corners, just not throwing tens of thousands at a mechanic I can barely communicate with. And finally, paint. Plus a bit of tidying up here and there.  
    • Nope, needed to clearance under the bar a little with a heat gun, a 1/2" extension as the "clearancer", and big hammer, I was aware of this from the onset, they fit a 2.0 with this intake no problems, but, the 2.5 is around 15mm taller than a 2.0, so "clearancing" was required  It "just" touched when test fitting, now, I have about 10mm of clearance  You cannot see where it was done, and so far, there's no contact when giving it the beans Happy days
    • It's been a while since I've updated this thread. The last year (and some) has been very hectic. In the second-half of 2024 I took the R34 on a trip through Germany, Italy, France and Switzerland - it was f*cking great. I got a little annoyed with the attention the car was getting around Europe and really didn't drive it that much. I could barely work on the car since I was living in an inner-city apartment (with underground parking). During the trip, the car lost power steering in France - split hose - and I ended up driving around 4,000kms with no power steering.  There were a few Nurburgring trips here and there, but in total the R34 amassed just shy of 7,000kms on European roads. Long story short, I broke up with the reason I was transferred to Europe for and requested to be moved back to Japan. The E90, loved it. It was a sunk cost of around EUR 10,000 and I sold it to a friend for EUR 1,500 just to get rid of it quickly. Trust me, moving countries f*cking sucks and I could not be bothered to be as methodical as I was the first time around.
    • I assume clearances were all a-okay?
×
×
  • Create New...