Cylinder heads job and shopping list

[silverbullet]

I have one of the Heritage-type valve spring tools. It's so quick and easy, you'll wonder why you ever bothered with a universal one!

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[Syncronorth]

Coming a bit late to this, but some thoughts for you:

I understand you might want to work out a budget for the rebuild, but you really need to find out what is wrong before talking yourself into spending loads of money.

Have you actually confirmed the diagnosis of a failed seal - as far as I remember it's still only a strong suspicion.

Just because there is a water leak does not mean that there is anything wrong with the heads themselves or valve gear. By all means dismantle and inspect, then replace as necessary, but i am not a supporter of simply replacing everything with new, especially given the variable quality or aftermarket parts.

I have a similar spring compressor to itchyfeet, except mine is about 35 years old

If you are short of time, and need the van back on the road quickly then I understand that may be driving you towards having ready to install components on standby. Be aware that you will probably / should spend much more time cleaning components than actually assembling, and most parts are available overnight. Valve guides will best be done by a machine shop, and they can be booked up / take time to do the work.

Get a compression test done before you disassemble. That will tell you something about the condition of your heads, piston rings and which cylinder is leaking. I use one of these https://www.ebay.co.uk/itm/Gunson-HI-GA ... 3294253417

Thanks for your advice. I'm not 100% sure it is a failed seal or why there is exhaust in the cooling system. In my experience it is cheaper to replace one or two extra parts then paying a mechanic for the diagnostic. But you have a very strong point regarding the quality of aftermarket parts.

I have ordered two new amc heads and will have a machine shop take out valves from an old head and put it all together. I have an old DJ engine laying around that I'm planing on paying someone to rebuild in the future so this heads will be used to that project if I don't need them now.

Thank you for reminding me to do the compression test. Is there any other test before I take out the heads that can tell me witch cylinder is faulty?

Also wondering how I can tell the condition of the heads when they are out? Seen on YouTube people doing leak test filling them with water and looking for leaks, is it more I should look for?

Thanks for the measurements itchyfeet

I have one of the Heritage-type valve spring tools. It's so quick and easy, you'll wonder why you ever bothered with a universal one!

Was going to order it from vwheritage but it don't say it suitable for T25.. But it probably is?

[937carrera]

I use both a compression tester and a leak down tester when diagnosing engines.

Compression testers are cheap to buy and easy to use.

Leak down testers are better for diagnosis before stripping down (you can know if it's rings, head gasket, intake or exhaust valves), but they are more expensive, you need a decent compressor and they are more expensive. Good ones are much more expensive

The compression test should give you a view of the overall condition of your engine, plus which cylinder is leaking. Do a wet test as well as a dry one and you should get a view on the condition of the rings, but that's more difficult to do with a flat engine.

[Syncronorth]

Will this set do the job or is it trash? https://www.amazon.co.uk/KKmoon-Cylinde ... way&sr=8-2" onclick="window.open(this.href);return false;

I have access do an powerful compressor but no idea how to use the leak down tester but guess I need to learn that

[Ciaraneng]

Will this set do the job or is it trash? https://www.amazon.co.uk/KKmoon-Cylinde ... way&sr=8-2" onclick="window.open(this.href);return false;

That one seems to only go to 7 Bar. I'm not sure what type of engine you have (might be worth listing your van type and engine type in your signature) but from memory the wear limit on a DG engine is 8 Bar. Plenty of compression testers on eBay that seem to do the job...

[Syncronorth]

Started the work today and hoping to run the car on Sunday




There's one clean manifold port, is this the one I should suspect giving me trouble?

Just realised I forgot to do the compression test, luckily there's still oil in the engine so won't take too long going back a few steps.

[Syncronorth]

Cylinder
1 3
4 2

[937carrera]

Well, they all look pretty decent and close to each other.

Number 3 is just a bit lower, so that may be a sign of where the leak is.

With that information, unless you really want to, or spot something when the heads are off, then I wouldn't bother touching the valves at all, just remove the heads, inspect and refit.

You really should have done that 3 weeks ago

[Syncronorth]

Well, they all look pretty decent and close to each other.

Number 3 is just a bit lower, so that may be a sign of where the leak is.

With that information, unless you really want to, or spot something when the heads are off, then I wouldn't bother touching the valves at all, just remove the heads, inspect and refit.

You really should have done that 3 weeks ago

Haha yes probably should, but I'm not worry about having new Cylinder heads laying around, I strongly belive it's better to have T25 parts then money in the bank


Just finished getting the heads off. Started with cylinder 1 and 2 and everything seemed fine got the disturbing click/squeeze sound on all 8 nuts from what I understand is normal. On the other side the nuts went off very easy and without any sound also the metal ring head gasket from nr3 did fall out as soon as the head was out. This is also the same cylinder with the clean port.

Should I assume someone replaced this and didn't torque it down correctly?

Also found something looking like antifreeze limestone

[937carrera]

Should I assume someone replaced this and didn't torque it down correctly?

That's one hell of s smoking gun with a lot of evidence, so the answer is almost certainly yes

Also found something looking like antifreeze limestone

I suspect that is what you get when pink coolant is used when the blue isn't fully flushed out - they react with each other and make gunge so I understand

[Syncronorth]

Should I assume someone replaced this and didn't torque it down correctly?

That's one hell of s smoking gun with a lot of evidence, so the answer is almost certainly yes

I'm feeling lucky today



One hour and no sign of leaking, guess I should start cleaning and get them back on?

Bentley says apply cylinder head sealant on gasket side facing cylinder head.. Seen many places online where people seem to do both sides.. Any opinion?

[937carrera]

If itchy doesn't chime in himself, best look at one of his rebuild threads

https://forum.club8090.co.uk/viewtopic. ... 7&t=162895

Warning, if you get sucked in you'll be a day or more reading through all the links, it may be easier doing a search in a thread or by author

Those heads are ready for a clean and refitting, the liquid test is simply confirming what was learnt from the compression check - 13 bar is like a new build

I found diesel is a good cleaner, with brake fluid to clean them off

[Syncronorth]

Ended up doing a small amount off sealant in the head gasket groove.

Everything back together and the car is running smoothly. I'm very satisfied! Thank you for all the help.

[937carrera]

Thanks for posting back with the update and good news that the problem is fixed, it is always good to hear the end of the story .

Did you bother removing the barrels, or just decide to pop the heads back on and torque correctly ?

[Syncronorth]

From what I understand it's no fun removing the barrels when the engine is in the car so didn't have a go on that. Only replaced the green seal. Also replaced the water pump, temp sensor so hopefully I won't have any problem with the water in the near future.