How good is a P5 heater and vacuum take off question.

[stan]

Hi I would expect the 3 litre straight 6 to push out decent heat yet the heater seems to be just mildly warm rather than toasty? I know cars of this period generally had poor heating but my 1966 Moggy can easily toast bread within a short startup time so why not this? Likewise the temperature guage doesn't seem to go much higher than 1/3 across the scale?
Duff thermostat maybe? I know its a recored radiator and everything else looks ok, the water value seems to move as needed? Heater matrix maybe bunged up or an air trap? The previous owner flushed and refilled with fresh water/antifreeze?

Water pipes seem to look in good condition?

My second question ( sorry for all these questions btw) but I noticed this banjo type vacuum connection just behind the carb, with no pipe connection? Engine was running so I put my finger over it and felt a light vacuum?
Does anybody know what it should be connected to please? I dont like loose ends so to speak.


Thank you.

[stan]

Nov 9, 2017 20:59:56 GMT @dicky said:

I don't know much about the 3 Litre engine but with reference to your last paragraph, that looks like a take off for a vacuum gauge and needs to be capped to prevent the mixture running lean or simply fit another vacuum gauge to it to help tune and monitor the engine.

Thank you Dicky. I capped it off earlier today just in case.
If it was for a gauge, thats fine will leave it blanked off.

Thats another off the worry list.

Stan

[Deleted]

Try holding the two water pipes on the heater with the engine running and hot. If the inlet is much hotter than the outlet it might indicate the heater matrix is blocked.

[Phil Nottingham]

Dicky's answer with the extra vac take off is correct. The heater will be too hot for your legs if both the matrix and heater valve are not clogged up - I think the output is 4Kw = a 4 bar electric fire

[stan]

Nov 10, 2017 10:00:04 GMT @kevbacon said:

Try holding the two water pipes on the heater with the engine running and hot. If the inlet is much hotter than the outlet it might indicate the heater matrix is blocked.

Thank you Kev good idea. Will try tomorrow but I have to say its very well insulated anyway , even without decent heat I never felt cold on the home trip.

Stan

[stan]

Nov 10, 2017 18:13:37 GMT Phil Nottingham said:

Dicky's answer with the extra vac take off is correct. The heater will be too hot for your legs if both the matrix and heater valve are not clogged up - I think the output is 4Kw = a 4 bar electric fire

Wow sounds perfect that should keep the family happy and me, I hate the cold.

Thanks Phil.

Oh forgot to mention, if the demister lever is set to off does all the heat go to my feet? Keep trying different options but cant get a definite answer?

[Phil Nottingham]

Yes it should do but the foam seals on the heater box flaps go to powder so leaks occur including cold air intake

[stan]

Nov 11, 2017 22:13:34 GMT Phil Nottingham said:

Yes it should do but the foam seals on the heater box flaps go to powder so leaks occur including cold air intake

Thanks again Phil

[stan]

I checked the pipes this morning. The inlet and outlet pipes are both warm, not hot though, but I did notice the outlet is crushed against the cylinder head which cant be helpful can it?
All the pipes seem to have been replaced but I think this one has been cut too short hence the issue?
Do these have a sharp bend premoulded onto the block?

I also put my hand on the top radiator hose above the thermostat and again it wasnt especially hot just very warm?
Do you think I have a faulty sticking thermostat?
The car was apparently restored in 2005 , presumably a new thermostat fitted then? They should last shouldnt they?



Thanks in advance.

[Phil Nottingham]

The crushed pipe will not help but it looks like poor circulation through a blocked core in the heater or a blocked valve. The top hose should remain cold until the engine is fully warmed up which takes time on these cars - the heater should be hot well before then. If the stat is the proper bellows one it fails safe ie open and the engine and heater will run overcool. If the later modern waxstat is fails closed which will eventually cause overheating

[stan]

Nov 12, 2017 10:14:30 GMT Phil Nottingham said:

The crushed pipe will not help but it looks like poor circulation through a blocked core in the heater or a blocked valve. The top hose should remain cold until the engine is fully warmed up which takes time on these cars - the heater should be hot well before then. If the stat is the proper bellows one it fails safe ie open and the engine and heater will run overcool. If the later modern waxstat is fails closed which will eventually cause overheating

Thank you Phil.

Ok I will get a new pipe and route it so its not squashed, whilst its off will backflush the heater matrix and check the valve is opening closing?

Thanks again

[enigmas]

Why not remove the thermostat and check its rating (160, 180, 195 ??) and function by immersing it in a boiling pot of hot water. It should open smoothly and fully. The rating should be stamped on the body of the thermostat. I recently checked a pair that had been in place for over 15 yrs and both functioned perfectly. Lifespan of thermostats is very difficult to determine...they either work or they don't...but it's easily checked. The kinked hose is also working against the efficient function of the heater core.

[stan]

Nov 12, 2017 10:27:14 GMT enigmas said:

Why not remove the thermostat and check its rating (160, 180, 195 ??) and function by immersing it in a boiling pot of hot water. It should open smoothly and fully. The rating should be stamped on the body of the thermostat. I recently checked a pair that had been in place for over 15 yrs and both functioned perfectly. Lifespan of thermostats is very difficult to determine...they either work or they don't...but it's easily checked. The kinked hose is also working against the efficient function of the heater core.

Thanks for the advice, I will give that a try or maybe just get a new one and have done with it?
This is the trouble with old car ownership you never know who has or has not done work to the car?
You have to love previous owners and their bodge half a job ways. Haha

[Deleted]

If you hold the top of the thermostat housing and start the engine from cold it will suddenly go from cold to hot if its working OK. If it very gradually goes to warm or hot then its possibly stuck open.
This avoids taking the thermostat out to check in boiling water,although its probably only worth it if you think the fixings are seized or dont have a new gaskets to fit.

[stan]

Nov 12, 2017 13:17:56 GMT @kevbacon said:

If you hold the top of the thermostat housing and start the engine from cold it will suddenly go from cold to hot if its working OK. If it very gradually goes to warm or hot then its possibly stuck open.
This avoids taking the thermostat out to check in boiling water,although its probably only worth it if you think the fixings are seized or dont have a new gaskets to fit.

Thanks will give that a try.
I did notice today after a run, the top hose to heater box was hotter than before and the out hose to block was warmer. I did gently tapping the thermostat housing and the water valve also with abblock if wood in a feable attempt to see of it made a difference?
I then moved the watervalve open/close as far as it would go a few times and heard a descisive click when it reached max travel so wonder if cable had stretched a bit? I also carefully lifted the squashed water pipe over a little to see if it would open up a bit??
This car is a daily driver and lives outside and the more I have used it the more its loosening up and driving better everyday, so it probably needs its legs stretching. I just want to get the heater fixed as I want to use it for a trip to the my works office which is 200 miles away.
I should get a modern eurobox but hey where is the fun in that?

[Deleted]

Maybe its flushing the heater matrix out slowly and a bit at a time as you use it. I'd be tempted to drain the cooling system into a bowl and see how much rubbish comes out.It can do no harm anyway.
No,you dont want one of those modern things,I have a range rover (sort of a younger relation to my P5b) and they are known for leaking seals on the heater.Its a full days work to get at them apparently and involves cutting holes in the trim.Sounds like fun.

[stan]

Nov 13, 2017 10:07:21 GMT @kevbacon said:

Maybe its flushing the heater matrix out slowly and a bit at a time as you use it. I'd be tempted to drain the cooling system into a bowl and see how much rubbish comes out.It can do no harm anyway.
No,you dont want one of those modern things,I have a range rover (sort of a younger relation to my P5b) and they are known for leaking seals on the heater.Its a full days work to get at them apparently and involves cutting holes in the trim.Sounds like fun.

Thanks Kev. I ordered some 3/4 hose to replace the rear, I noticed whats been done now, they either cut it too short or fitted the wrong hose?
There is a hose clip on the front of heater box which I guess is to hold the hose clear of the block ( thank you PO). So its getting ditched. I doubt even Rover would have cables or pipes resting against something else.
The thermostat top pipe is getting hot now as is the inlet pipe just that pesky outlet isnt quite there. PO says he flushed it all but maybe he left airtrap in there also. Its getting a backflush whilst I am on this.

Will update once done, I know everyone is so excited by this cliff hanging thread? 😀

Good luck with the rangerover.

[Phil Nottingham]

You can easily tell if the valve is opening fully by checking the lever on it is full travel - its only a piece of rubber like a cistern ball valve washer and they can decay and in the inlet can block up anyway

[stan]

Nov 13, 2017 12:40:47 GMT Phil Nottingham said:

You can easily tell if the valve is opening fully by checking the lever on it is full travel - its only a piece of rubber like a cistern ball valve washer and they can decay and in the inlet can block up anyway

Thanks Phil.

2 weeks before my trip, got my thick winter coat just in case. 😀

[Deleted]

Incidentally,that vacuum take off looks like it could have been for the old fashioned vacuum operated screen wash system.

[stan]

Nov 14, 2017 9:58:52 GMT @kevbacon said:

Incidentally,that vacuum take off looks like it could have been for the old fashioned vacuum operated screen wash system.

Well that must have been better than the lucas electric one!
Its like peeing through a miniature straw!
I gave up purchased an inline motorpump and bypassed the lucas one, just plugged new piping to the outlet from the bottle.Its still pants so I removed the tube underneath the bottle head and pushed a new one straight onto base of the bottle, sort of ok for 1 minute then useless.
Have ordered new tubing and will cut it as short as possible and take it from there.
I fitted a cheapo Chinese washer bottle with built in motor to the moggy minor and that effectively jet washes the windscreen its that good, however I wanted to keep it looking original in the Rover but then I would like to see where I am going, so might end up with the same option?
By contrast my old Beetle pressure washer still works after 25 years.
I just dont leave it on the spare tyre incase the valve fails and flattens the tyre.

[stan]

After driving the car for a week, the heating has improved a little.
I have the new thermostat and water pipe to fit at the back of the engine ,antifreeze and was about to do this tonight however decided just to check the state of the water and looking where to drain it? Well I think I have seen cleaner looking muddy pool with pigs in them?
A decent backflush thermostat and pipe replacement should hopefully do the trick? Wondering if the thermostat is silted up with this sediment?

Btw I ordered the 82 degrees thermostat, is that the normal one for our climate ? Why is there an 88 degrees one also?

Old cars are great if they are not peeing oil on the drive they are doing something else.

[Phil Nottingham]

82 deg is OK - no higher.  The heater should not be poor but really hot

[stan]

Nov 20, 2017 22:10:35 GMT Phil Nottingham said:

82 deg is OK - no higher.  The heater should not be poor but really hot

You were right. I finally went for a test drive over t'hills after my late night flush (ooer) and thermostat replacement.

Other than constantly watching the temperature guage ( bad experiences with an Armstrong Siddeley years ago) it was spot on.
Engine warmed up fairly quickly and temperature stayed on normal even when going uphill with gusto.
The heating ,good grief, I had to open the window and turn it down, a first in this car.
Engine ran well and I left it ticking over to see if it would get hotter but no stayed in position as it should. Superb.
This is one of the good things when buying old cars you can generally make things better and get a sense of achievement.
If the oven goes pop I know where I can do some baking.
Onto the next job that pesky RF supression tonight hopefully try not to drop anything behind the engine void somewhere!