Head gasket blowing.

Hi Folks I think I might have a leak in my head gasket....no overheating but coolant being forced out after normal driving. I have replaced the radiator cap...fan works ok when I've run it up to temperature, stationary....no load on engine.No water in oil or vice versa. No apparent leaks anywhere else, hence the suspicion falling on the head gasket.    
I am going to have a compression test done which should confirm the diagnosis.
Before I shell out for the garage to fit a new gasket. I 'd like your views on Steelseal or similar for gasket repair.....anyone had experience of using such stuff.?
My feeling is that I've little to lose (£40.00) if it does not work and I have to go the new gasket route.
Second question, I live near Birmingham...anyone know of an Ace cb 500 mechanic in the area? 

if its leaking on the water side then a compression test will show nothing, all its doing is sucking air in and blowing it out of the expansion tank. if its leaking on the oil side then you will find residue in the water.
if the head gasket has gone then dont mess about with a quick fix, just put a new gasket on, theyre not expensive and not hard to do, i did mine in a couple of hours.

I always fix things myself, can be a pain sometimes but you learn with every job and your confidence grows. None of our bikes have ever visited a garage for more than an mot, guess I am just lucky that ive grown up with my dad knowing a lot, so just learned from him, plus if there is anything I can't do, or if I am afraid I might break something,I just get my dad to show me how to do it properly lol.

Replacing the head gasket isn't too bad - have a read of the Haynes.

It is probably more difficult to diagnose if the head gasket is actually the problem...

Hi Gents....I think your all correct in that I should get to know my cb better, so when I am sure what is causing the over pressure in the radiator I will have a stab at fixing it myself.....thanks for your input.
Wonkster.

Wonkster wrote:Hi Gents....I think your all correct in that I should get to know my cb better, so when I am sure what is causing the over pressure in the radiator I will have a stab at fixing it myself.....thanks for your input.
Wonkster.

I think you have probably made the right choice: even if you end up spending lots of money on tools, in my experience, this is cheaper than what most garages charge!

For God's sake don't put rad-weld or k-seal near it; it clogs the expansion pipe at the top of the filler neck. Also pull out the thermostat while you are doing the HG; you will probably find it has opened too far and needs popping back on the spindle.

teamster1975 wrote:For God's sake don't put rad-weld or k-seal near it;....

Also pull out the thermostat while you are doing the HG;.... 

a couple of good bits of advice there.

Thanks Guys I am going along the stripping it down route and having a close look at everything I dismantle so there are no mysteries if I have a problem whilst riding the Stelvio next year.  Thermostat is the first thing I shall be checking. Thanks for the good advice and encouragement. Will keep you posted.
Wonkster.

Hi, and Happy Christmas,

What's coming out? Coolant, steam, oil? Enough to stain, drip or pool under the bike?

I'd say pretty good advice so far. Tank off, check condition of everything, change plugs etc whilst you are there too.

Imo headgasket fail is not too likely, just like on a car it = water from the coolant system getting into the oiltight engine system. Key symptoms, off white emulsified oil on the diptstick and under the radiator cap, falling coolant level. N.B. old oil can mimic this.

Also, the temp guage never seems to get much above the little white bar on my bikes, never mind halfway so if the guage goes towards the red, = less cooling going on and suspicion falling on head gasket.

Btw my bikes steam a fair bit following a week or two being stored in the damp part of my garage.


atb
m1

Hi Muttley1, a very Happy Christmas to you & yours.

The symptoms are that the cooling system is over pressurising...no water in the oil.....no oil in the water.......no overheating. Last run was back from Hatton...20 miles or so.....coolant dripping from front of engine and overflow tank. 4 days later tank off ...still pressure in system....overflow tank full.....coolant level well below cap....no overheating. The test of choice would be a block test but as that's not available to me I am going down the opening her up route to see what's gone wrong.  I will check the thermostat first and all the hose connections by close examination.....if this proves inconclusive I will continue to take the head off and check it and examine the gasket.
I have sourced all the gaskets,O-rings etc from Mick'sGarage.co.uk who appear to be the most reasonable ( unless you know better. )
As soon as my pal makes some room in his lock up I will make a start.
ATB Wonkster

Also worth checking the earth wire hasn't snapped off the rad fan while you're tinkering; it should be attached to the top fan bolt where it's fixed to the rad, if it has gone astray you can strip the wire and wrap it round the bolt.

radiator blocked?

Thanks Teamster & Tricky will check both of those items. Wonkster.

Hi Guys, I started stripping the bits & pieces off, checking as I went.....thermostat working fine in a saucepan but not positioned correctly in its chamber.......fan earthed OK.....radiator fixed on the outside with plastic padding or similar!!!! Whilst it hadn't leaked  once I'd seen it I knew I had to replace it so a new one is on order. Carried on stripping down.....valve cover off......camshafts out....cylinder head off......MLS gasket not showing signs of blowing so I was a bit stumped. Before you all cry in unison why didn't you check this first, I know I should have, and at least 2 of you told me to......I tried to blow down the overflow tube from the filler neck to the expansion tank.......BLOCKED. Removed the expansion tank end and applied air pressure.......out pops about 100mm of congealed radweld or similar.

I feel a right Wally but at least I now know my CB intimately.

So whilst I am in this position I will have the head skimmed and I will regrind the valves in.

New gaskets and seals going in for the rebuild, an expensive lesson with tools and replacement rad, but I am so pleased to have sorted it.

So glad I listened to you Guys and didn't put more crap into the radiator in the form of cylinder head sealant.

So radweld might get you home but flush it out as soon as you can.

Will let you know when she's back on the road.

Cheers, Wonkster.

at the end of the day youve learnt things and gained experience, nowt wrong with that. glad youre sorted.

Tricky. wrote:at the end of the day youve learnt things and gained experience, nowt wrong with that. glad youre sorted.

I couldn't have put it better myself.