Removing heat exchangers DAF 46

[stevethenortherner]

On dismantling my 46 engine, I have removed the engine from the car and barrel ducting, I have removed the 3 nuts from the exhaust manifolds on the barrels, but the exchangers are refusing to budge, even with some fairly persuasive tapping with hammer and screwdriver.  Any suggestions as to why they won't move and remedy?

[starider]

Hi, Have you removed the two nuts and bolts each side where the silencer bolts on and you have to remove the small cross member which links the heat exchangers. On the nearside heat exchanger you need to remove the small pipe which goes from the heat exchanger to the inlet manifold.
If they still remain immovable you may have to remove the studs from the cylinder head,you do this by using losening each manifold nut just a fraction and locking it with another nut,then use a spanner on the inner nut to undo.It may help to pour very hot water on the cylinder head as the aluminium expands much more and quicker than tthe mild steel studs.Once the studs are out you should be able to spray a little WD40 around the pipe and rotate the whole exchanger from side to side enough to break any "seal" and the pull off.

[bobdisk]

Same happened on my 33 engine. I removed everything Starider said, but still no luck. so I took the heads with the stuck manifolds/heat exchangers to an engine reconditioners. The valves needed replacing and seats doing anyway, so I asked them to remove them. It was a (censored) of a job. They heated the heads with a flame and cooled the manifolds at the same time, and forced them apart somehow. That is what I was told. They have never come across anything like it. They were stuck because of disimilar metal corrosion. The manifold pokes into the head, its not a flat joint like other manifold to head joints. its that which causes the problem. Its common on Daf air cooled engines. Has the car been standing un used for a while? it will probably be a job for professionals like mine was.

I have some posts elsewhere on this forum on this subject.

[starider]

Seems bobdisk had real problems,if my method doesn't work and before getting too drastic: if the clutch housing and drum are removed and the engine drained of oil,carefully stand the engine upright on it's back and pour plenty of WD40[or similar]around where the pipes go into the heads/exhaust and leave for a few days and try again. Please remember not to be too brutal as you are dealing with a soft metal and too much use with a screw driver can damage/destroy mating surfaces.
I must admit with all the 33/44/46 engines I have stripped, I have never had any real problems removing heat exchangers, but as bobstik quite rightly says these engines are now very old and if not used the old disimilar metal corrosion can and does take effect. Good luck!!

[bobdisk]

Good luck, I hope it works for you, but I cant see it. I believe the engine company tried something like that before the heat treatment. Where you put the release fluid (WD40's Fast Release Penetrant or Plus Gas or equivalents) keep a regular eye on it every hour or so and dont let it dry out, as they evaporate fairly quickly. As I said, mine had to resort to heat treatment by experts to get them apart. If I had tried, I expect I would have damaged them somewhere.

[starider]

Remember, no two"jobs" are the same,you were very unlucky, as I said I've never had any real problem removing heat exchangers. The tip with using a release liquid is to mix the WD40/Plusgas with a little engine oil/Redex,there is then less evaporation.
I have worked on DAF cars for over 50years and because most of the survivors have been little used and often left in the open or damp buildings,corrosion caused by water ingress/condensation is becoming more of a problem as the years roll by.
Unfortunately any DAF which shows low or very low mileage and hasn't been dry stored should be viewed carefully as low mileage means little use and all sorts of corrosion issues
I firmly believe that anyone who owns a DAF and restores/keeps their DAF in good running order, deserves a"medal", and the hope that we few keep these marques on the road.

[Richard DAF Webmeister]

Oct 29, 2020 23:39:36 GMT starider said:

I have worked on DAF cars for over 50years and because most of the survivors have been little used and often left in the open or damp buildings,corrosion caused by water ingress/condensation is becoming more of a problem as the years roll by.
Unfortunately any DAF which shows low or very low mileage and hasn't been dry stored should be viewed carefully as low mileage means little use and all sorts of corrosion issues
I firmly believe that anyone who owns a DAF and restores/keeps their DAF in good running order, deserves a"medal", and the hope that we few keep these marques on the road.

Very true, Tony. That's one of the reasons that I have a strict policy really of only owning one DAF at a time. We have seen so many times over the years, as indeed have other classic car clubs, of people buying "just another one" with the best of intentions, but of course you can only drive one at once, and time races by. The result is that lots of lovely old cars just left standing, slowly rotting away and seizing up.

Seen it all before, then that's even few of the cars left for anyone else in the future.