Possible causes of Over Heating

[barefootbonzai]

We put a B18C SIR into a EJ8 but the car has an overheating problem, sometimes we can go a whole day and not an issue. Some days it just heats up all the time.

What could be the cause if it's not any of the follow:

Thermostat
Thermoswitch
Radiator
Water Pump

What else can cause the engine to overheat?

[EGB16A]

i'm assuming your not losing any coolant? maybe somethin is blocked?

[heist]

i seem to ahve the same problem with my car barefoot.... some days its fine, the next it overheats all the time..... i would also like to know the answer....

[bennjamin]

headgasket ? If there isnt any visible leaks this is where the coolant might be going.
Is the ECU throwing a code ?

[barefootbonzai]

We'll check the ecu next. Just haven't paid any attension to it cause the engine light is always on, do to some lazy wiring on the O2 sensor on my behalf.

[iamhappy46]

as a bandaid for overheating, try turning on the in-cabin heater to get some heat outa the motor fast. pain in the @ss during summer but it could save a headgasket

[SKREMN]

does the fan turn on???
are you leaking / loosing any water?
no water in your oil or oil in your water??
how old is your coolant?

[shmivic]

check coolant/water ratio
if you have too much coolant in it will overheat

[ECU-MAN]

fan it self could be rooted, when does it overheat
traffic lights, while cruising

how sure are you your radiator and thermostat are ok

[Limbo]

Blockages or crap coolant? I had crap coolant and it caused me to overheat for no reason.

Faulty temp sensor?

Are you loosing coolant? or is just the engine temp raising?

[[[d a n n y]]]

happened to me b4

thermo stat is on the way out

mine was like that for about 1 month.

then the thermo stat just lost it and car overheated heaps

so most liekly thermostat is on the way out or could be a fan switch..

[barefootbonzai]

Thanks for the input guys. So pretty much a car shouldn't overheat if the list i put up top is all in good nic. We have replaced the thermostat with no luck. So we'll replace the rest of the list this weekend.

Was just scared that the engine just might be g a y.

[wynode]

Ok so tell us when it overheats. At lights (when not moving) or while moving? :)

Also have you flushed the coolant system properly (maybe start there as that is often the easiest / cheapest. Good to do it after you've changed your thermostat (kill 2 birds with one stone).

If that doesn't do it it could be a blocked radiator as said. Are you loosing coolant? Is the coolant colour ok? What does the radiator cap look like?

Let us know!

[destrukshn]

well.. have you tried bleedin the system?
also..
i had this problem as well..
where the temp gauge will sometimes go up.
and when i changed my earth cables to fatter ones.
it had fixed the problem, and never came back up again.

[barefootbonzai]

To answer all the questions.

It overheats both while still and even when driving sometimes.
Coolant levels are always good, and coolant is a nice colour.
Radiator cap is the stock one.

Since we already changed the thermostat the other nite, radiator doesn't seem to be blocked, so we gonna change the thermoswitch and fan and see if that helps.

Any pointers to how to flush the system? Where is this heater control i hear about that will let the coolant continue to flow through the system?

I will check all the grounding too if you think that could be an issue.

Thanks heaps guys, keep the idea's comming.

[wynode]

How do you know the radiator isn't blocked?

I did a DIY on a coolant change. For a flush, just drain all your coolant (including the block) and run some clean water through. Then fill it up with coolant.

It's possible you have air in the system too. How's your oil looking? Does it look milky?

[Weq]

does the coolant overflow when it heats up? Maybe its not a heat issue at all, rather a wiring/bad sensor?

[barefootbonzai]

i'm just asumming that the radiator isn't blocked cause when you open the thing on the bottom to let the water out it runs fairly smoothly.

How do you get water running through the system? ie, keep the theromstat open?

Yes coolant overflows when it heats up.

Yeah could be a wiring problem, we will check these up on the weekend.

[Jase EK]

could it be u using d series radiator on b series engine ? i heard that has an effect on cooling.. different sizes..

[SKREMN]

water can still flow well from a tap but still have blockages internally

[wynode]

^ as above

As said I believe b-series are twin core and d-series are single core radiators.

[Slow96GSR]

^ as above

As said I believe b-series are twin core and d-series are single core radiators.

You would be correct in that assumption.

[barefootbonzai]

All very good ideas. But i'm running my CXI radiator on my B18 with no problems what so ever. He's using his VTi radiator which should be the same if not better. So i don't think it's the size.

But the blockage thing could be true. We will be trying my raditor and thermoswitch on his car this weekend and see how it goes.

But it's good that every idea is related to one of the ones from the list. Our main concern was that the engine was just stuffed somewhere internally.

[barefootbonzai]

Any pointers to how to flush the system? Where is this heater control i hear about that will let the coolant continue to flow through the system?

[wynode]

Heater control = putting your heater on the hottest setting to make sure you get all the coolant out :)

To flush the engine, drain all the coolant and fill up the coolant system with clean water (some use distilled water). Then start her up for about 30 seconds and let the water run through (I step on the gas a couple of times to build up some pressure via the water pump). Don't run the car for too long as it is just water in there. Then drain and repeat depending on the condition of the water.

You can also darin the engine block (drain bolt is located just under you headers on the front of the block).