Expansion tank/radiator cap

[TheSebringOne]

Hi guys n gals, whilst running the car for about 30 mins today to charge the car battery as can't be bothered to put trickle charger on, steam started to out come out the back above the glass hatch! Opened hatch and engine cover and found it was coming from around the expansion or radiator cap. This might be a stupid Q, but after checking it that its screwed on tight, I assume I need a new cap? Any ideas how much and do I approach the usual vendors? :(

[AR]

Are you sure is the cap and not the tank?

Barry will probably have one, if not Honda £££ or any of the overseas vendors.

Cheers,

AR

[TheSebringOne]

Ary I think its the cap as steam was seeping underneath and around it, I also checked the pipe that has a clip that goes onto the top of the tank where it fits over a brass/copper inlet and that seems ok. Will check again tomorrow. Thanks

[NSA]

I think Honda charges £15+ for the cap. My tank had split around the seam on the side and I ended up getting an aluminium tank and cap from Dali racing. Worked well and was a doddle to fit. I think about £100 delivered.

[Kevin]

Is it on tight? There are two stop-click positions.

Edit: I also thought, you were idling the car for 30mins? Did the radiator fans come on? Maybe they didn't and the water is boiling over?

Idling like that does't raise the oil pressure much, so you have a cold engine, running, with low oil pressure.....nice. Maybe better to actually go out and drive it.

[dan the man]

james take the cap off when cold and check how good the seal is etc.. or just take it for a run and see if it does it again.

or do the same as u did but watch it and if it looks lie its gona do it switch it off rapid and then diagnose better.

U werent trying boil rice on the engine were you ???

[TheSebringOne]

Thanks guys, just to confirm I had car running for 30 mins stationery, the cooling fan did come on near the front rad and I checked that the cap is tight to the point the cap will not turn/tighten anymore as it hits a stop/kink! Will run car stationery again at weekend and see how long to boil the long grain American rice, not sure the anti freeze would taste nice Dan! I have contacted Bazza already :) HUK wanted 41.28!! The parts man was astounded too as normally 10 to 15 squids for lesser Hondas:angry:

[TheSebringOne]

Ran the car stationery today, Its NOT the cap! Its leaking out where the copper pipe sits bewteen two plastic seats on the top of the plastic tank, at the back of the copper head to which the cap screws on. After letting the car cool off, I took off the cap and the only thing I can see that air/coolant can leak through is the brass tube thats seems to be welded into the round lip. Surely it can't be leaking throught that!? I guess it a new expansion tank then!! :(

[dan the man]

copper and brass? wonder if i could solder it up james?

[TheSebringOne]

Thanks for your offer, may take you up pal :) I'm no expert, but the copper tube that you can see once the cap been removed inside has a round groove/depression gap, maybe its seeping through this under pressure? or the whole copper top that sits on top of the plastic cap is leaking? I think its maybe the former as that same area is leaking on the outside near this thin cooper tube that sit in bewteen two plastic seats.

[dan the man]

Ill have to take a look at mine when i get time..unless u get pics up. Might be too thin copper for me to mes about with, but if we take it out s0oldering iron might be doable

[TheSebringOne]

If you take off the cap pal, you know what I mean. (only when the car cold tho! ) I think it can be repaired by taking off the tank, soldering it by filling out the round groove where the copper tube is welded to the round part of the copper top. Or maybe trying a hamerite type product that heat, air and water resistant. Then if that does'nt work, then a new tank it will be!

[jaytip]

It sounds as good a time as any to upgrade to a stainless one.

[Kevin]

Sounds like a bodge repair. A good candidate for water spewing out while driving. There's a least one car here that has had a new cylinder head because the water leaked out, and overheated.

Get a metal one. The plastic one will crack one day anyway.


If you take off the cap pal, you know what I mean. (only when the car cold tho! ) I think it can be repaired by taking off the tank, soldering it by filling out the round groove where the copper tube is welded to the round part of the copper top. Or maybe trying a hamerite type product that heat, air and water resistant. Then if that does'nt work, then a new tank it will be!

[TheSebringOne]

This Q is linked to the coolant leak thread. Would I have to bleed the system when changing the expansion tank and/or pressure cap since I've only lost a little coolant and not a big leak? Was planning to change them and just put in Honda pre mix to the max level. I've only ran the car stationery for half an hour twice to charge the battery only, not driven it.

[NSXGB]

If it's only leaked through the expansion tank \ cap, you will not have to bleed the system, it's the highest point of the system.

If you are changing the tank, you can just clamp the bottom hose (es) while you do the job, then just top up.

[TheSebringOne]

Thanks, I thought so, but wanted to make sure. Hopefully Honda parts Dept are open today on Xmas Eve!?, so I can get the anti freeze and sort it out before New Year! Maybe weather permitting, a nice drive as shes been stationery 6 weeks!

[Steveycaz]

If it's only leaked through the expansion tank \ cap, you will not have to bleed the system, it's the highest point of the system.
...if the car is level. I'd open the bleed points anyway IIWY. The whole routine took me about an hour on Saturday, and all you need is a wrench with 12mm socket and a pair of pliers for the heater pipe bleed cap - I replaced 2 litres of coolant.

[TheSebringOne]

Can't believe it, but the local Honda dealer (parts) was open to 12! So got two one litre at 10 squid! :angry: Could have got the big 5 litre for about 18 squid and that will do the whole car! Maybe I should have, as think its due a coolant change next year What is the service intervals for this?