Hi,

How does someone diagnose loose heads on a 1600TP?

How hard is it to fix the problem? Is it just a case or removing the engine and retorquing the studs or is more major work needed?

I'm suspecting my Beetle has this issue but need to decide whether to fix it or look for another engine.

Thanks,
Brett.

Diagnosis: experience is the reality, as loose heads doesn't always show up with a compression test. Basically you'll hear a blapping noise with heavy throttle especially on a cold engine as the barrel gets longer when it heats up so a mild case can go away as the engine warms up.
The noise is literally the combustion process escaping between the head and barrel, it's like the head hitting the barrel with a hammer so a bad case can pound the engine block where the barrel seats which will reduce the effectiveness of just retensioning, which is the first step to repair. If it comes back, you can expect to do a rebuild so machining can repair the cylinder locations.
One important thing is if retensioning, clean, tap and lube all threads, nuts and studs so tensions are correctly applied to the fasteners.

Thanks Matt,

Sounds about right. I thought it was an exhaust leak at first. It's hard to start and runs poorly until warmed up and makes a ticking noise from the left (or passengers) side of the engine. Now a couple of weeks and maybe 150km later it's audible above about half throttle when fully warmed up. Seems to still go okay though.

I've tried to find a video of the sound so I can pinpoint it, but nothing I've found online sounds similar.

Once I've got the engine out will I see visible signs such as carbon around the head to barrel join?

Usually the lower studs are worse, pop off the tappet cover and look behind the rocker gear at the 4 x studs, you may see them loose. Sometimes the studs are pulled out of the case... = bad
Carbon, sort of, but usually the head is filthy there anyway as the lower headstuds are in the oily environment and hence leak there. Upon reassembly, seal these as you refit.

it can get realy bad ,
http://www.youtube.com/watch?v=kXnEBQF4WB0 

Could it be a cracked head?

Can you see a blow mark on any of the spark plugs?

That can have the same symptoms I would guess??

Hi,

There's no blow marks on any of the spark plugs. I pulled them all out today to check if any were oiled or sooted up. I only fitted them a couple of weeks ago and they all looked good.

Fortunately it doesn't sound anywhere near that bad Ian.Mezz. It sounds pretty much like a loud exhaust leak to me. I have it booked in at my mate's exhaust shop tomorrow. I'll still take it in and see what he thinks. He's also a mechanic. He used to own a split screen and he loves my Beetle.

The engine bay seal is a bit crusty and I'd like to replace the tar boards on the firewall. So it's not all bad if I have to pull the engine. I don't feel like rebuilding it over Easter weekend. But if I can get away with simply cleaning up the threads and retorquing, then I will be happy.

this is were they leak.
http://www.youtube.com/watch?v=n6LuGWku7d0 
between the head and top of the barrel

Len agrees. Loose heads. Easter weekend, engine pull. My scruffy MR2 is off the sub bench. Lucky I didn't sell it yet.

I have unexpectedly good news.

When I went to collect my Beetle tonight I was greeted with a big grin and "It's fixed."

Len (Werribee Exhausts) found after I spoke to him at lunchtime that a nut was missing where the extractors bolted to the left rear of the head. There was a huge exhaust leak there. He replaced the gaskets and refitted the exhaust with new nuts, washers and clamps. The noise is gone and the car runs perfectly. The mongrel didn't ring me and tell me the good news!

At my request Len also made up some link pipes from the stock heater boxes to the rear tinware area so the heater flexi hoses could be connected just like stock. He also rebent the pipe to the muffler so it tucked up under the guard properly. Now the muffler doesn't scrape going in my driveway and it's running nicely again.

I should point out this stainless extractors and "tuckaway" system was fitted by a well-known VW repair shop in early December and the car immediately went into storage until early Feb. It's probably done 1000km total since then. The exhauast hung low from the day I picked it up from that specialist. So I wasn't real happy with it.

Gotta be happy with that.