Engine oil coolant box getting very hot.
 

Hi,
I have a 2002 bugeye wrx scoob.
My engine oil coolant box is getting very hot ( i know it is supposed to be hot). But it's to the point where steam is emerging from the bonnet, even after a short journey. Because of the heat, it is evaporating the remaining water that is in there and i'm having to constantly top it up. Could anybody help me diagnose whats causing this? Or maybe someone else has had this problem?

I got to work this morning and some Dick thought my car was on fire and covered my scoob with a powder fire extinguisher :mad:

Oil coolant box?

Sorry. My terminology is poor. In the manual it just said it was the engine oil coolant. On the left hand side if facing the car. With a radiator style cap on it. I would post a picture, But im not able to yet (probably lack of posts). I think it could be just the cap itself as water is leaking out onto the top of the unit in question. This would be so much easier if i could post a picture.

header tank?? it should get hot, some times the caps let out a bit of steam but if its being forced out with alot of pressure could be a headgasket failure

Are the engine temps rising by anychance?

Thanks for the replies. Hope it's not the gaskets. Water is leaking out of the top of it. Maybe seal on the filler cap? No the engine temps are normal, no rise at all. Is there anyway i can send/put a picture on here that you can view. I've been reading the faq's but cant find when or how many posts i need before i can post a picture ( if this is the case?)

Could be a faulty cap.

Join www.photobucket.com and upload to there, then post the [img] link on here.

http://i1148.photobucket.com/albums/...pseeab4493.jpg

Cheers for the heads up on photo bucket. hopefully that url is the photo.

It's the header tank.

Could be the cap, could be the system pressurising due to a stuck shut thermostat, (although they TEND to stick open), and it could be headgaskets.

Get sniff test done.

Thanks for the reply and the info. I'm hoping it's the cap. I will search the forum to find out what a sniff test is as i'm a total noob :cry:

Cheers :cool:

May be easiest buying a new cap 1st then? Or make sure your current one is on correctly/tight?

Sniff test: any decent garage will do it, they will be checking for hydrocarbons in the coolant, which gives notice that the h/g is gone.:(

You refer to this as the engine oil coolant box. Are you filling it with oil?

You are talking about the header tank are you not?
This is the coolant header tank and takes water, topped up with antifreeze from time to time to keep the correct strength, water : antifreeze mix. A new pressure cap is inexpensive and as suggested has to be your starting point. Halfords will fit it for you. FOC.
The temperature guage on your instrument binacle measures this coolant temperature. The needle should be half way on the scale and as long as that is the case your coolant temperature is probably OK.
On the right hand side of the engine bay as you look at it is the oil filler cap. It is at the top of a black tube and is usually yellow in colour. It is easy to recognise because it usually has 710 embossed on it. This is where you put the oil but do not over fill. If you read the handbook you will see instructions regards oil level.

Hi,
I am sorry again for my poor terminology. I couldn't find how to change the post title after i'd found out how ****e my wording was :lol: Yes i know the header tank is for water only. I have been topping it up as needed. :) Temperature guage is normal, just below half way. I've been at college all day, so tomorrow i will take it to get a new filler cap and get a sniff test done. Thanks for all the help everyone. Fingers crossed it's not the head gaskets :Suspiciou

If you don't get a filler cap drop me an email per profile and I will send you one out £10 including postage. If you have been putting in a lot of water you need to bring the anti-freeze strength up. The anti-freeze serves two purposes. Obviously it stops the coolant freezing and cracking the block and it also acts as an inhibitor to reduce products of corrosion within the cooling system.
In view of recent weather trends it would be wise to protect down to -20 C.

Or....swap it with the other cap and see if it still does it. You`ll know if it`s the cap then.

Hmm. Something else occurs to me and that is that having looked at an overflow tank this morning you sometimes find that the overflow spiggot on the top can become loose allowing water to weep and the other thing that has happened quite recently on one of the zinc die cap "oil boxes" :) is that there is a leak between the top and the main body. The top is held in place by some small set screws 8 or 10mm I cannot remember and on a recent water header tank :thumb: one of the set heads was broken off. There was a small leak from the seam between the top and the body. Although a very small leak it was quite spectacular as it was dripping on to the hot turbo. (the tank had been relocated further back on the engine).
Just check these two possibilities.

Remember a hot box is preferable :)

they are 10mm btw, dont overtighten them btw, sometimes worth taking the lid of giving it a clean and putting a smear of sealant where the gasket sits

Hi,

Quick update. My local garage were retarded and didn't know what a sniff test was (so won't be visiting there again). I went to visit a friend today who has had about 4 or 5 scoobys. He checked the bottom hose on the radiator and noticed it was stone cold. So hopefully it's the thermostat. also checked for blockage in the tube from the expansion tank, which was ok. Could someone please recommend where to get a decent thermostat from? I looked on ebay and there are loads for £15. but idont know if those ones are cheap crap? Again thanks everyone for your help and advice on this matter.

http://www.ebay.co.uk/itm/Genuine-Su...item414fcabe37

This is the one im looking at. Genuine so i take it this will be fine?

Yeah that'll be fine. Possibly cheaper from Alyn @ AS Performance, 0191 410 3770

Import carparts are very good btw.

Right. Just got home from changing the thermostat and replacing the coolant, and discovered that the header tank is leaking from the neck of the tank. There is slight visable corrosion around the neck of the header tank. Noticed small bubbles around the neck. So it seem's the header tank itself may be at fault? If not we are into the dreaded h/g area now :o(

Zinc diecast or plastic header tank?
I will have a metal one here I expect.

I'm not sure to be honest Harvey . Definitely not plastic. Just a bog standard One. If you have got one, can you let me know a price as I need to get one asap. I'm at college at The moment so won't be able to reply again till later this evening. Thanks.

( just looked it up, It's metal)
(Dont worry about it i have just ordered one, Sorry couldn't wait )

Also think I may have an airlock after changing coolant. Temp gauge was up and down between the middle 2 markers this morn, on my way to college. Temperature usually sits aboout 1 needle width above the first marker before the coolant and thermostat change, now it fluctuates up to the second marker. It actually went beyond the second marker earlier and i had to pull over and let her cool down. Also the bottom hose of the radiator is stone cold all the time now and the top hose is hot.

Just to conclude this thread. The culprit was the header tank itself and a split tube that goes into the header. Picked up a second hand tank for £25 delivered and replaced one of the tubes, flushed and replaced coolant and now all is well. Thanks again to everyone that helped me. :notworthy