Key Aspects of the 1.6 AEE Engine Valve System:

Valve Clearance: Self-adjusting (Hydraulic lifters).

Engine Design: 4-cylinder, 8-valve, Single Overhead Camshaft (SOHC).

Maintenance: If tapping noise occurs, check for worn lifters, low oil pressure, or blocked oilways.

If the engine is noisy, it is likely a faulty hydraulic lifter needing replacement rather than manual clearance adjustment.

17 hours ago, Rsedmonds said:

I thought the 1.6 valves were hydraulic and non adjustable?

In that/this case take no notice of me, I forget which engines these cars have, which owners have swapped to what, Favorits to Felicias and so on and it's a bit of a crossover period and I can't remember my own name some days. I saw something the other day that reminded me of a possible heating cause but can I remember what it might be and where I might have seen it, no, but I might at 3am, and then forget it again.

2 hours ago, nta16 said:

In that/this case take no notice of me, I forget which engines these cars have, which owners have swapped to what, Favorits to Felicias and so on and it's a bit of a crossover period and I can't remember my own name some days. I saw something the other day that reminded me of a possible heating cause but can I remember what it might be and where I might have seen it, no, but I might at 3am, and then forget it again.

It’s not an issue, I don’t know the engines either so what you said made me think and if it provoked that reaction then we’re half way there. I’m very much cut from the same cloth when it come to memory retention so I believe you should say what you think (before it’s forgotten) because though 50% of what I say is wrong the other 50% is right and may just be the answer needed.

Blimey I couldn't get to 50% if I could remember. 😄

The only thing I can think of for what I might have forgotten I think you have already covered - you didn't replace the piston rings for new ones(?).

I’m starting to think about just ripping the engine out and replacing it with another.

What are the popular options for a swap?

9 hours ago, Rsedmonds said:

What are the popular options for a swap?

VW 1.4 16V AFH

Besides the drivers side engine mount, it's a direct fit.

Do you have a way to test exhaust gasses in the coolant circuit? The way it behaves still gets me thinking about gas bubbles blocking the flow. At idle, the leak isn't as bad, but once running, the pressure in cylinders is higher, which may result in more leaking.

Having been through HG issues with 1.3 (as any other person owning this engine), weird cooling issue was the early symptom. Radiator fan switching too late, heater issues, even ruptured coolant hose.

Maybe we should double check the coolant plumbing, too? Could you post a couple of photos of each hose going from/to the thermostat body?

12 hours ago, Papez said:

VW 1.4 16V AFH

Besides the drivers side engine mount, it's a direct fit.

Do you have a way to test exhaust gasses in the coolant circuit? The way it behaves still gets me thinking about gas bubbles blocking the flow. At idle, the leak isn't as bad, but once running, the pressure in cylinders is higher, which may result in more leaking.

Having been through HG issues with 1.3 (as any other person owning this engine), weird cooling issue was the early symptom. Radiator fan switching too late, heater issues, even ruptured coolant hose.

Maybe we should double check the coolant plumbing, too? Could you post a couple of photos of each hose going from/to the thermostat body?

I’ve done a sniff test on the header tank (the blue stuff in a tube) on numerous occasions Saturday gone and all have been negative.

Fan switches on when expected, the heater gets up to temp and it has new coolant pipe all round which has increased the pressure in the system helping reduce the temp slightly.

I’ll take a picture of the hoses layout tomorrow and post.

Also I have compression of 16 bar across all cylinders. I’m being told by mechanics that in general that’s fine. but I’m being given figures quoted as official of a maximum pressure 15 bar.

Hi,

This a picture of how i have the thermostat housing piped up on my 1.6 AEE engine.

What I will say that I've forgotten to add previously is the car is OK around the streets on the estate as there's a lot of stop start at junctions. but as soon as I get on a long road the temp will gradually build up and within 5 minutes will sit at the 100 degree mark as previously pictured.

11 hours ago, Rsedmonds said:

This a picture of how i have the thermostat housing piped up on my 1.6 AEE engine

That seems to be correct, as far as I can see in the service manual.

Regarding the compression, how precise is the measuring device? If you haven't skim head too much, there's no reason for it to be higher.

12 hours ago, Rsedmonds said:

previously is the car is OK around the streets on the estate as there's a lot of stop start at junctions. but as soon as I get on a long road the temp will gradually build up and within 5 minutes will sit at the 100 degree mark as previously pictured.

This is the weird part. The heating works, so there are no bubbles. It cools down on idle, so pump likely works, too. If only high power is the problem, it's like cooling capacity of the system is somehow limited.

You mentioned earlier that hoses remain soft, is that still the case?

Two things to mention, before I forget, suggested by another member, first not known to me and second I think I had forgotten about in this thread at least -

one) - we might have already cover this, if the plastic expansion tank is new check the tubes/ports/out/in/lets are not block or partially blocked from manufacturer

two) - I don't think this has been tried but I might be wrong, checking temperature with an external device (on writing this I remember someone doing this but not if it was you Rob) infrared gun or an app on a phone to look at an image for hot (or cold) spots or areas.

Great photo btw, and labelling, very useful (not to me as I don't know, but you and others).

1 hour ago, Papez said:

Regarding the compression, how precise is the measuring device? If you haven't skim head too much, there's no reason for it to be higher.

This is the weird part. The heating works, so there are no bubbles. It cools down on idle, so pump likely works, too. If only high power is the problem, it's like cooling capacity of the system is somehow limited.

You mentioned earlier that hoses remain soft, is that still the case?

I’ve used 3x compression testers and they all read the same give or take 0.5 bar.

The head was skimmed but I’m not sure how much was removed but the skim limit was still visible. Unfortunately I didn’t take a picture of it after it was skimmed.

Yes the radiator hoses were soft and pressure in the header tank was low. I’ve replaced the hoses with same bore pipes that were fitted 32mm & 19mm.

4 hours ago, Rsedmonds said:

The head was skimmed but I’m not sure how much was removed but the skim limit was still visible. Unfortunately I didn’t take a picture of it after it was skimmed.

That may be the reason for higher pressure, but I don't think it's the cause of overheating.

4 hours ago, Rsedmonds said:

Yes the radiator hoses were soft and pressure in the header tank was low. I’ve replaced the hoses with same bore pipes that were fitted 32mm & 19mm.

Did it help?

I've got one more idea to test out.. bridge the connector on the radiator fan, so it runs constantly. It probably won't be enough to keep the engine cool while running, but if it does something, it may suggest some issue with airflow.

As with removing the thermostat if you have the fan running constantly you will have to run the engine for a bit longer and/or put more stress/load on it for it to fully over-warm compared to with thermostat and fan controlled. Obviously you don't want to load or stress the engine more until it is fully warmed up (oil temperature) to normal running temperature.