"New" CU problems

[81AirCooled]

Hi, I've picked up my new 1981 2.0 ltr Aircooled van tonight and I've noticed a couple of potentially nasty problems. I'm new to T25s and really don't have any experience repairing cars and don't have a tonne of cash to throw at problems either. I would prefer to fix things myself so could do with some advice on these problems I've noticed.

1) Heating stinks. It`s like a smell of burning rubber when I turn it on. As soon as I turn it off the air is much better, except when I stop the van and it comes back a little bit. I don`t know whether its exhaust fumes or engine fumes, the engine seal isn`t in good condition though. I`ve noticed the same/similar smell walked around the back of the van so think it might be exhaust.

2) Engine was running fine for about 30 minutes, enough power, no strange noises. I stopped the vehicle at the services for 5 minutes, then drove for another 20 odd minutes before having to stop again to go to an ATM. Each time the engine started no problem, idled nicely and I was able to drive another 20 mins home without any issues.

I then left the van standing 10-15 minutes. Once I started it again it struggled while idling, cutting out several times unless I was giving some revs. It was still doing this after a 10 minute drive as soon as I stopped and didn`t a few revs up. I haven't had any chance to investigate yet, and I probably wouldn`t know where to start so any step-by-step advice would be grealy appreciated.

[ermie571]

Not sure about the heating....


But the engine.....it could be sommat or nothing. As a newbie to these engines you can't start better than a full service, so that you know that everything is sound. Cap, rotor arm, leads and plugs, oil and oil filter.

As its Aircooled, the vacuum leads will be vital...if they have fallen off lumpy running will ensue! Chokes working properly? When the engine is running, spray all round the carbs and manifolds with wd40 - if revs pick up, you have an air leak.

That enough to get you started and familiar with your engine? Firing order 1 4 3 2.....

oh - a dodgy coil could produce thoses symptoms too, as well as a poor idle stabilisation unit....water in the fuel, blocked fuel filter etc etc


Good luck

Enjoy!!

Em
xx

[gsmoke]

Does the heater smell oily at all?
What can happen sometimes is a small leak from either pushrod tubes or rocker gasket drips down onto the heat exchangers and the fumes find their way to your vents.
If it is this, (which I suspect), dont stress, you can replace these seals easily.

[81AirCooled]

Does the heater smell oily at all?
What can happen sometimes is a small leak from either pushrod tubes or rocker gasket drips down onto the heat exchangers and the fumes find their way to your vents.
If it is this, (which I suspect), dont stress, you can replace these seals easily.

I suppose it could be. The smell is kind of hard to describe, it quite biting I think, like something burning. My wife sat in the back at one point but couldn't smell anything until she got out and went around the back so I suspect it's something like you say and it's coming through the vents when not moving. I'll be buying a CO alarm tomorrow, I want to be on the safe side.

[81AirCooled]

Not sure about the heating....


But the engine.....it could be sommat or nothing. As a newbie to these engines you can't start better than a full service, so that you know that everything is sound. Cap, rotor arm, leads and plugs, oil and oil filter.

As its Aircooled, the vacuum leads will be vital...if they have fallen off lumpy running will ensue! Chokes working properly? When the engine is running, spray all round the carbs and manifolds with wd40 - if revs pick up, you have an air leak.

That enough to get you started and familiar with your engine? Firing order 1 4 3 2.....

oh - a dodgy coil could produce thoses symptoms too, as well as a poor idle stabilisation unit....water in the fuel, blocked fuel filter etc etc


Good luck

Enjoy!!

Em
xx

I'll certainly be checking for air leaks tomorrow, I should also be able to change plugs/HT leads and dizzy cap if required over the next couple of days. What I find strange is that it ran for 30 odd miles no problem, even idling and starting no problem after short stops but has problems after a longer 15 minute stop.

mmmm, makes me wonder if its the auto choke, where and how can I find and test this?

[81AirCooled]

I drove the 25 miles to work today, which went well for the most part. The idle was an issue while the engine was still cold this time but during the drive I had no issues at all and it idled nicely while I parked up at work and left it for a few minutes while I tried to locate the source of the fumes/smell in the van.

I checked the seal on the back door which looks fine and appears to due it's job ok. I could also move around the back of the van and didn't notice any burning smell at all. When I got back to the cockpit the smell was back again but I couldn't locate the source. With the heater on cold and turned on the blower but there's clean air coming from all the vents I can find. During lunch I will turn the heater on and give it another go, the stench is so bad then I should be able to locate it.

By the way, 8 amp fuse is the right one for the wipers? The thing is missing

[81AirCooled]

Another thing, when I went to the back of the van I could hear the usual sound of the engine ticking as it cools down but I could also just about hear tiny popping sounds like something was sizzling or simmering. I know the CU's run at over 100°C so wondered if this was a common occurance. I don't have a temperature gauge installed yet but the engine was running fine too.

[gsmoke]

8amp fuse is correct for the wipers.
I dont know about your sizzling. I would have a look around above and below the engine. You may find some sausages!
If something was frying, you should see the damage. I often get paranoid and hear allsorts from my engine. Its worth a good look round though, especially when its doing it.
With your heater, look under the van for any oil drips, to the left or right of the center of the engine. You could remove the heatshields that live between the heat exchangers and the case (with a screwdriver) and have a proper look.
Unless someone has done something daft like fit a rubber hose between the exchangers and the heater control pods, I cant think what else it could be.

[ermie571]

Hi Mate,

glad you are getting somewhere...the problems with idle at cold certainly sound like choke issues...

Right...folks will now need to know what set up you have - standard carbs or has someone put sommat...er....interesting on there?

sizzling.....doesn't smell petrolly does it when you park up....petrol boiling in the carbs if something modified under the lid?

regards

E
xx

[paul66beetle]

Could be old worn heat exchangers. The exhaust fumes go through a sealed heat sink with the heat exchanger, air that passes over gets warmed up and passed into the cabin. If the internal passage for the exhaust fumes is damaged/corroded/holed then fumes can escape and get mixed up with the air that is supposed to be heated up.

Quite common on Aircooled bugs, I'd imagine T25's are pretty similar. You can buy J-Tubes which are cheaper that replace the exchangers with direct tubes but you loose the heating element, which in a camper is needed really.

[geordie skydiver]

It's almost certainly worn heat exchangers and/or push rod tubes dripping into the heat exchangers... been there, drove me mad for months as I just couldn't afford to replace them.

When I did, the smell cleared up, I put on - new heat exchangers (not cheap), new heater pods (medium cheap), new push rod seals and rocker cover seals (cheap) and gave the underneath of the engine a good old degrease and jet wash.

Good luck.

[81AirCooled]

I've just been out to have another whiff in my lunch break. The smell is almost non-existant when the heater is off and I'm moving and gone if I have the window open a half inch. When the heating is on I can really smell it coming from the heating vents.

I'll have a look under the van when I get home and it's cooled down but assuming it's the heat exchangers or oil dropping into them and they are about 200 pounds a pop is it safe to drive over long distances simply with the heater turned off? I can imagine fitting J-tubes in future though as the van will not be in use during winter.

As far as the engine cutting out when I stop and the engine is cold goes, I found that it only happens in drive (automatic) and not when I pull up in neutral. Does this still point to the choke?

[paul66beetle]

I've just been out to have another whiff in my lunch break. The smell is almost non-existant when the heater is off and I'm moving and gone if I have the window open a half inch. When the heating is on I can really smell it coming from the heating vents.

I'll have a look under the van when I get home and it's cooled down but assuming it's the heat exchangers or oil dropping into them and they are about 200 pounds a pop is it safe to drive over long distances simply with the heater turned off? I can imagine fitting J-tubes in future though as the van will not be in use during winter.

As far as the engine cutting out when I stop and the engine is cold goes, I found that it only happens in drive (automatic) and not when I pull up in neutral. Does this still point to the choke?

J-tubes are the cheap option if you are not bothered about heating. Switching off the heating should stop fumes coming into the cabin, as it should shut the flaps. Heat exchangers are not cheap. Keep your eyes open for a good second hand pair

[Gunslinger]

Not sure where you can get cheap J tubes from for a type4 square port engine. Be interested to know though although I've already got mine on order from Turbo Thomas. However that does mean I will have a set of heat exchangers for sale soon if you're interested

[fullsunian]

The easy thing to do with the smelly heater is to just disconnect the cables off the heater pods, the flaps will spring back to cold and stop the smell. You can reach the cables and pods through the rear wheel arches. This is not going to help though when winter comes, only real fix is sort oil leaks out. This could well be your sizzling too...warning....I have seen a van catch fire due to this type of oil leak
IAN