How to tell if cyclinder head or gasket has gone?

BristolBingoBongo · Post by **BristolBingoBongo** » Wed Mar 14, 2007 11:37 am

Advice needed.

Same old problems with overheating bongos. In august of last year we discovered 2 hoses had holes and they have now been fixed and the coolant has been flushed. The Bongo is again having over heating problems so we have taken it to a garge in Bristol. They have said that the cyclinder head or gasket has gone and this is going to cost us anything from 800-1600 pounds ouch!

They say that they are 100 percent sure of the head gasket due to an emissions test. Before we go ahead with spending lots of money on my bongo I would like to be sure. Does this sound about right?

Also when I asked about if the coolant was bled they said it was difficult to fully bled the system because it was so large. This doesn't sound right so could anyone recommend a garage in Bristol or Bath that understands Bongos?

The last time it overheated there was still lots of coolant in the system which would lead me to think it was more an air lock problem or a blockage.

I have read lots of posts on overheating bongos but I really want to be sure before I get the work done as we are rather poor.

Post by **Ian** » Wed Mar 14, 2007 11:42 am

I'd get it seen to by Bell Hill Garage. They know all about Bongos, are near Bath, and you won't get better service. Their ad is on the Home Page of the main website.

Veg_Ian · Post by **Veg_Ian** » Wed Mar 14, 2007 12:12 pm

That kind of response doesn't exactly fill you with confidence in their ability does it?

A quick test for failed head gasket is to remove the rad cap and start the engine up (you will need to remove the air cleaner ducting to get to it, 2 screws/bolts IIRC). Only do this when cold, start the engine and look for discolouration in the coolant (mucky brown) and for air bubbles. Either of these two symptoms would indicate that exhaust gas from the cylinders is entering the coolant and yes, a failed head gasket or even worse a cracked head.

However, the only sure way to check is to get the system pressure tested. Any decent garage should be able to do this for you. I'm not sure I would place your last garage in that category though ...

Veg_Ian · Post by **Veg_Ian** » Wed Mar 14, 2007 12:15 pm

Sorry, didn't make the distinction properly there. It's the radiator cap you want to remove not the cap on the expansion bottle.

BristolBingoBongo · Post by **BristolBingoBongo** » Wed Mar 14, 2007 1:05 pm

Thanks for your tips. The coolant is def a muddy brown color

When it last overheated we opened the coolant cap to add more water and lots of brown water poured out.

I will try the Bell Hill Garage

Veg_Ian · Post by **Veg_Ian** » Wed Mar 14, 2007 1:53 pm

Hmm not looking good - sorry!

dandywarhol · Post by **dandywarhol** » Wed Mar 14, 2007 3:57 pm

The emissions test used is to check for hydrocarbons - it can be done with a 4 gas analyser. It's pretty foolproof.

Veg_Ian · Post by **Veg_Ian** » Wed Mar 14, 2007 4:12 pm

The emissions test used is to check for hydrocarbons - it can be done with a 4 gas analyser. It's pretty foolproof.

Not heard of that one dandy. Please explain further. What's being tested for here, a high concentration of water vapour?

RobnKathryn · Post by **RobnKathryn** » Wed Mar 14, 2007 5:19 pm

Hi

I sympathise with your situation having been in a similar situation i.e. overheating bongo + empty bank account!

If you get a conclusive diagnosis from a garage about whether the head gasket is gone or the head is cracked, don't be afraid to consider doing the work yourself. I'm no mechanic having only experience of basic servicing tasks in the past, but by following the guidance in this forum and particularly the factsheet in the members section. I managed to replace, water pump, all belts, thermostat, timing belt, exhaust manifold, and cylinder head.

Had I just replaced the cylinder head and gasket it would have cost under £600 + my time. Had I replaced just the cylinder head gasket and head bolts it would have been under £200. If you do decide to go down this route, here are a few additional tips:

1. Don't just replace the cylinder head gasket without getting the cylinder head pressure tested for cracks. This is a specialist job and you'd need to take your head to a specialist. Mine charged me £40 for a preassure test.

2. If when you remove the exhaust manifold you see white flakey bits in the exhaust ports on the head, there's a very good chance the head is cracked.

3. The bolts on the front end of the exhaust and exhust manifold and turbo will be rusted up and very stiff and brittle. Spray them liberally with PlusGas (much better than WD40), the day before you plan to do the work, and again before you actually start.

4. Replace your timing belt and tensioner and spring at the same time, if it hasn't been done recently. You have to remove it anyway so it makes sense to renew it. Good factsheet in member section.

5. If you buy a new cylinder head, make sure you get new bolts too, and make sure the head includes valve guides. There are widely varying prices on ebay so check whats included carefully. I got a new head with complete gasket set and bolts for £400.

6. If you have to replace head, don't try to remove your cam shaft/valves etc yourself. Just take the complete head to your cylinder head specialist along with your new head and get him/her to transfer the bits from one to the other and set the tapppets. He will also then be able to tell if valves need replacing (4 of mine did)...only £6 each though.

7. If you replace the head, when you fit the new bolts, there are two smaller bolts to the front. Don't try to torque these up to the same degree as the others. They will strip the threads in the block.

8. If you replace the head get your exhaust manifold skimmed to avoid sheared studs in the future. About £30-40 by the cylinder head man.

9. On the drivers side of the head there are lots of rubber tubes, you'll probably break some of these taking them off because they're very brittle.
Don't worry to much, they're easy and cheap to replace. Consider diasabling your exhaust gas recycling mechanism, it's easy and means that the green bit you'll break when you remove it becomes unnecessary so it'll save you £40. Do a search for 'inlet manifold sludge' to get lots of info on this subject.

Lastly, if you do this yourself, make sure you allow yourself plenty of time. Mechanics will laugh but I'd reckon on day to read up about the job, plan your sequence and get necessary tools etc, then a good full day to strip everything down. Then you'll need to take your head to a specialist for pressure testing etc. If it's found to be cracked, then you need time to get new one, and transfer cam etc from old to new, and get exhaust manifold skimmed. This could easily take a week. Then a day and a half to get everythin gback together.

I hope this post is of use. Sorry it's so long. But if you do sort the job yourself you'll be sooooo satisfied. Mine runs better than it ever did now.
Done 5,000 miles with no problems so far. Actually I can't believe this post is so long..........good job I'm being paid to do it! I'm going to look daft if turns out you've just got a duff thermostat!

All the best..........Rob

dandywarhol · Post by **dandywarhol** » Wed Mar 14, 2007 6:55 pm

Veg_Ian wrote:
The emissions test used is to check for hydrocarbons - it can be done with a 4 gas analyser. It's pretty foolproof.
Not heard of that one dandy. Please explain further. What's being tested for here, a high concentration of water vapour?

You run the engine with the cap off Ian and let the gas analyser probe "sniff" the vapour. If there's unburnt combustion gas (HC) in there it's from the cylinder/s.
It's a pretty reliable early warning check

Harry · Post by **Harry** » Wed Mar 14, 2007 7:28 pm

I'm a bit bothered about the reference to muddy brown water in the radioator.

As far as I can recall every vehicle I've owned - from my first minivan in the 1960s has had 'muddy brown' coolant in the rad within a few weeks of a coolant change whilst the colour of the top up header tank has remained normal - green/blue/clear etc.

My Freda does not overheat - run hot - etc except on a couple of occasions
1. When the bottom hose froze up. - It soon cleared.
2. When the water pump packed up.

In both cases coolant became hot and boiled but I stopped before i cooked the engine.

Do I have a cracked head - it certainly feels like mine's cracking up.

H

francophile1947 · Post by **francophile1947** » Wed Mar 14, 2007 8:27 pm

Agreed Harry, muddy brown water was almost obligatory with cast-iron blocks and heads - I haven't looked at my Bongo's though.

Veg_Ian · Post by **Veg_Ian** » Thu Mar 15, 2007 8:32 am

Cheers for the reply Dandy

mikeonb4c · Post by **mikeonb4c** » Thu Mar 15, 2007 9:14 am

I was as surprised as you lot to find the coolant in my Bongo crystal clear (but green) when I drained it, and to find water clear as a mountain stream issuing from the rad when I backflushed it. Never had that on my old British cars

BristolBingoBongo · Post by **BristolBingoBongo** » Wed Apr 04, 2007 4:51 pm

Hiya - just a quick update.

Following from BongoMasters advice we took the van to Bell Hill Garage near Bath. To get there we drained the coolant and did it properly following the correct procedure and it drove the 15 mile journey without any overheating problems. Clearly its a small or very intermitant water loss.

The previous garage had clearly created an airlock when they looked at it, they also said afterwards 'we've only ever seen a couple of these'. I will send a private email to Ian as i would like them removed fom the approved garages.

Anyway, get to Bell Hill garage, really nice people and clearly know what they are doing. The result: a couple of corroding core plugs and a very slight cracked cylinder head. (ouch!)

So we are going to get it done (thanks to Mr Visa card) but it begs the question how long has the crack been there (we only had the van since june) or could it have been caused by the air lock created by the previous garage? Who knows but we're going ahead with the repairs and hopefully we will have a 100% reliable van for the summer.

Keep an eye on your water levels.