Over heating

I’m running a RB25DET motor in a S13. The car over heats, but only when I drive 200+km and keeping it there for a while. I have taken out my thermostat but then it gets hotter faster so I replaced it. I’m running my CA18 water temp sensor, a 3 core alloy radiator and a bottle system so it has no airlock I am also running 2 12” fans in the front. I have tested it with out my bumper for more air but it still over heats.
Any body :?:

My 2c... Check you radiator cap is holding pressure, FMIC is too close to your rad, 12 inch fans not powerful enough, head bolts not evenly torqued or your hg is going. Im not the expert though.

make sure your fan are flush against the radiator

Drillergy wrote:

My 2c... Check you radiator cap is holding pressure, FMIC is too close to your rad, 12 inch fans not powerful enough, head bolts not evenly torqued or your hg is going. Im not the expert though.

all is cool. The fans dont work on 200+km anly air caming from the front.
Thanx

rat wrote:

make sure your fan are flush against the radiator

The fans are flush. I run one 14" before and still the same, but on hi speeds the fans dont work. air caming in the front cools down the radiator.

Reyn S wrote:

Drillergy wrote:

My 2c... Check you radiator cap is holding pressure, FMIC is too close to your rad, 12 inch fans not powerful enough, head bolts not evenly torqued or your hg is going. Im not the expert though.

all is cool. The fans dont work on 200+km anly air caming from the front.
Thanx

maybe your radiator is not hardcore enough, sorry dont have any useful help

rat wrote:

Reyn S wrote:

Drillergy wrote:

My 2c... Check you radiator cap is holding pressure, FMIC is too close to your rad, 12 inch fans not powerful enough, head bolts not evenly torqued or your hg is going. Im not the expert though.

all is cool. The fans dont work on 200+km anly air caming from the front.
Thanx

maybe your radiator is not hardcore enough, sorry dont have any useful
help

im running a 3 core BMW radiator with alloy tanks.

it very common when puting different engine into S13! the thermostat tend to read different temp for CA18 and RB25~!
replace the thermostat and the sensor will do

dunno hey.. can think of a few small things,

check that the waterpump is actually pumping at full capacity, these pumps sometimes fail in such a way that the impeller sits loose on the shaft, thus not rotating same speed as the shaft..

make sure you are circulating the right way through the rad? water should enter top of rad and exit bottom back to motor.. only mentioning this because you using a differant rad..

if you are using a second hand rad, was it properly flushed? might be partly blocked?

an overheating problem in a car that has a non standard cooling system such as yours is hard to diagnose..

aep886 wrote:

it very common when puting different engine into S13! the thermostat tend to read different temp for CA18 and RB25~!
replace the thermostat and the sensor will do

Im running tha standerd RB25DET thermostat with the CA18DET temp sensor because im still running the standerd cluster.

Reyn S wrote:

aep886 wrote:

it very common when puting different engine into S13! the thermostat tend to read different temp for CA18 and RB25~!
replace the thermostat and the sensor will do

Im running tha standerd RB25DET thermostat with the CA18DET temp sensor because im still running the standerd cluster.

off topic but have you got everything working in the std cluster?

300sx wrote:

dunno hey.. can think of a few small things,

check that the waterpump is actually pumping at full capacity, these pumps sometimes fail in such a way that the impeller sits loose on the shaft, thus not rotating same speed as the shaft..

make sure you are circulating the right way through the rad? water should enter top of rad and exit bottom back to motor.. only mentioning this because you using a differant rad..

if you are using a second hand rad, was it properly flushed? might be partly blocked?

an overheating problem in a car that has a non standard cooling system such as yours is hard to diagnose..

The pump pumps at full I have checked but thanx.
I hade the “Radiator specialists” cum check the setup before they made my radiator. Thanx I will check.

hi had the same problem with my car and girlfriends car.

Car overheating at high speeds (not in traffic)

In both cases we had to get the radiater sonic cleaned. A normal radiator cleaner/flush wont cut it. The one radiatoer was new/reconned and we still had to send it back to get cleaned.

angelo wrote:

hi had the same problem with my car and girlfriends car.

Car overheating at high speeds (not in traffic)

In both cases we had to get the radiater sonic cleaned. A normal radiator cleaner/flush wont cut it. The one radiatoer was new/reconned and we still had to send it back to get cleaned.

My radiator is brand new

rat wrote:

Reyn S wrote:

aep886 wrote:

it very common when puting different engine into S13! the thermostat tend to read different temp for CA18 and RB25~!
replace the thermostat and the sensor will do

Im running tha standerd RB25DET thermostat with the CA18DET temp sensor because im still running the standerd cluster.

off topic but have you got everything working in the std cluster?

Yes everything works but my rev counter is out with 1500rpm's

what radiater did you use when you started the rb25 for the first time?

normally there is a lot of junk that has to be flushed from the import enjines. If you used the new radaitor when flushing the engine, this could of get stuck in you new radiator.

my thoughts

angelo wrote:

what radiater did you use when you started the rb25 for the first time?

normally there is a lot of junk that has to be flushed from the import enjines. If you used the new radaitor when flushing the engine, this could of get stuck in you new radiator.

my thoughts

I started it fith the CA18 radiator.

Based on all the information, it sounds like you could have head gasket problems.

What happens to the oil temp (if you have a seperate gauge for it)?

Are you still running the stock oil cooler/water heater in SA really?

What about doing a bleed down test per cylinder? I know the theory and haven't done this exercise myself.

You need compression tester - just fitting that goes into spark plug hole
Compressor with tank

When engine is cold:
Remove radiator cap
Set piston 1 to its closed cycle (all valves closed)
Connect compression tester connector and line from compressor to cylinder via plug hole.
Open Compressor air pressure.

Theoretically there should be for bubbles in the water if there is a problem with the head gasket (don't know if the air will leak through the closed thermostat though or whether it may come through the bottom pipe/cold pipe)

hope this helps

I’m still running stock oil cooler.

I don’t know, I don’t have a oil temp gauge

T took the car to a radiator place and they tested my the water for exhaust gases but nothing.

Thanx man

Something that helped me alot when trying to solve these kinds of problems is fitting an aftermarket water temp gauge to the car , but mounting the temp sensor just as the water leaves the engine before it is cooled down ie. B4 going to the radiator .

One can see any differences very quickly and it's a faily accurate way of making sure its ok. It's also independant from your stock gaues etc and doesn't need any specific sensor to work . Just the one supplied with the gauge . Relatively cheap option for peace of mind .

Whe my fan comes on I can literally see the water temp drop by between 5-10 degrees.

my 4 c 😉