Rainwater leaks - standard locations?

[stephend]

Originally Posted by eeedelli

Hang on - are we at crossed purposes? I was meaning high up in the rear of the front wheelarches which (I think) is quite a lot forward of anywhere near the door, as the flappy air vent must be to the rear of the arch and that's well forward of the door too.

Sorry, just me not being clear!

I definitely have water emerging from the door seals as I described in an earlier post, and I definitely have water getting in at the w/screen header rail. What I don't yet know is whether that's the same water. That leak (or leaks) let water in even with the car parked.

Separately from that, I found a rust hole in the wheelarch, exactly as you describe, to which I've just finished making a welded repair. I think that could only let water in when driving, as spray/splash.

Hope that makes more sense. I shouldn't post when I'm half asleep...

[eeedelli]

Ah yes - the two potential lieaks were getting conflated there. That makes more sense now.

Ta,
D.

[john.wigley]

On re-reading this thread, I've just realised that David mentioned a secondary issue in his original post which I for one missed. In his concluding paragraph he said:

Winter is here and the heater on this particular car has always had a fairly restricted effect (especially compared with my 940 which is like an oven when on full) so it's often difficult to keep the screen clear with so much damp in there and I'm also concerned I'll have rotted the floor out if I don't get something sorted sooner or later!

Having owned both 7 and 9 series cars over the years, my own experience would suggest that there was little difference in heat output between the two models. I didn't measure it scientifically, or even have the house-hold thermometer in the car, but both were very efficient; much like the proverbial oven, David!

This leads me to question whether his engine may be running on the 'cool' side, perhaps due to a 'stuck' thermostat? Alternatively, cold air may be getting in - if there is indeed a leak - where it ought not to be, thereby compromising the heater's effectiveness?

If the car is presently fitted with a viscous coupling mechanical fan, removing it and replacing it with an electric one may improve the efficiency of the heating system. In conditions of extreme cold, fitting a partial radiator blind (piece of cardboard ) may improve things - but keep an eagle eye on the temp. gauge!

In Scandinavia I believe adjustable radiator blinds were available as an accessory and electric engine block heaters are also widely used - but they may be a step too far in our normally relatively mild climate.

Regards, John.

[kiloran]

My '92 940 non-a/c is still un-furnacelike. Thermostat changed and it was backflushed during the recent engine swap removing a lot of sludge. Still watertight as I'm not losing any coolant. It's better than it was but still not toasty.

[bob12]

As to rainwater leaks the 700/900 series have common suspect areas as mentioned above.

If you remove the carpet you should easily see the source. Sometimes if difficult to spot 'spray' around a light dusting of talc and that should show up the source when it rains.

The sealant on the large plastic plugs on the side wall of the footwells can fail. It's a simple job to refit with silicone sealant.

If the sealant on the window has failed. You may find some liquid window sealant will fix it. It did on the a small spot at the top cargo space side window on my 745.

Another area that may cause concern is rust coming up from underneath on the front floor pans junction between the fire wall and the pan. It's a fairly complicated junction of parts and can rust from underneath.

Another recorded problem is where the bonnet pull goes through the two panels forming void space at heater intake and engine bay fire wall. If the rubber void water vent on either side of the car is not kept clear of debris water cannot drain properly out of the void near the back of the wheel arch and rust will form with inevitable consequences.

Bob

[stephend]

I don't have a point of comparison, but my 740 has always warmed up quickly and the running temperature has been rock-steady whatever the outside temperature. I'm sure an electric fan would be quieter, and probably reduce the fuel consumption a bit, but the viscous fan does seem to do its job.

One thing I have noticed is that at a given setting, the heater does seem to run slightly hotter on a long, fast motorway run, and slightly colder at slower speeds. But as I say, the temperature gauge stays rock-steady once the engine's warmed up. Not quite sure those two observations add up - but that's how it is...!

[eeedelli]

Thanks folks. There are some interesting ideas coming up here.

Just for info, I think the engine temp itself is fine as the thernostat opens, leading to the top hose heating up after a few mins. The problem seems to be the flow rate through the heater. At setting 0 or 1 on the fan, it will provide moderately warm air but increasing the fan speed above that cools the heater core so much that the temperature drops right down. That suggests to me that there's little more than a trickle through the heater core. (It's tricky to get it to run completely cold in summer, too.)

My suspicion is that a previous owner might have replaced the valve and got the bowden wire(s) wrongly positioned, though I'm at a bit of a loss to see how. My cousin also runs a 1989 740 and his is like an oven when on full, so it's something about this particular car.

Regarding the void space. I thought the rubber drain flap for that was only on one side. (Can't remember which side it's on.) Are there actually two and I've missed one? I did a check a while ago that it was clear but I'll have to check it again, once the weather settles down after this storm passing over for the next couple of days.

I've had the driver's side under-dash plastic trays out for some time but can't see any evidence of dribbles down the bulkhead.

[bob12]

eeedelli - I am pretty sure without checking that there's a rubber drain flap thing on each side of the void. When it rains I get a nice flow of rain water on the ground on each side in way of the inner rear of the front wheel arches.

If not already removed you will have to get the carpet out of the way to really see what's what .... or not!

Usually on a B200F 745 I find the temp gauge is up to the middle mark within 3/4 minutes of driving and a little longer in cold weather.

I was wondering if you had a loss of heat on all setting. If people have been playing around near the heater ducting the tubing can easily disconnect in parts and affect the various combinations of heating vents.

Best of luck,

Bob

[eeedelli]

It sounds as though I shall have to go hunting for the other rubber flappy drain!

Getting the carpet out would be an almighty pain as I think the centre console traps it, if I recall correctly. (Probably the seat runners too.)

There's a thick rubber sheet backed with sponge foam that goes under the carpet and right up the bulkhead too. I've had the side inner sill cover off for ages to lift the carpet up there for inspection and often find it sopping wet beneath but there was no sign of dribbles going down behind it at the top where it starts on the bulkhead so it must be getting in lower down somewhere, or round the edges and seeping underneath where I can't see. Either there are two faults (one on each side) or it's getting in somewhere around the middle (completely hidden behind the centre console) and running both ways. Either scenario is possible, I suppose!

Yes, my temp gauge sits in the middle after about 3-4 mins too. Not quite sure what you mean by "I was wondering if you had a loss of heat on all setting." Do you mean fan settings or heater control setting? As I say, even with the heater set for full heat, you only get moderate warmth at 0 or 1 on the fan but as the fan speeds up to 3 or 4, the heat reduces to pretty much nothing.

That suggests to me that increased airflow through the heater core is pulling all the heat out of it because the hot water isn't passing through fast enough to replenish with more hot water from the head - just trickling through. It's possible that there are some air ducts off, as the airflow on to the windscreen on the driver's side isn't much cop but even if that's the case, it would be blowing hot air to somewhere and all that comes out at higher fan settings is coldish air. (Similarly, in summer, setting the heater to cold doesn't fully cut off the heat. It's as if the valve is only operating from ¼ to ½ of its intended range.)

[Ian21401]

Watch the valve whilst moving the heater control through it’s full movement to ascertain whether the valve is opening and closing fully. Try disconnecting the cable from the valve and check the movement of the valve. If the valve will move fully try moving it to the fully open position then running the engine to check whether properly hot air is generated and the hoses connecting the valve to the heater are hot. If it’s properly hot then I suggest that the operating controls were not adjusted correctly. On my non AC 940 it is possible to adjust the position of the Bowden cable by loosening the small spring clip which secures the cable outer to the valve body and moving the outer slightly one way or the other until full movement of the dash panel knob is transmitted to the valve lever.