Classic cars forum & vehicle restoration.

[MVPeters]

Shell27
When I saw your original post, my first reaction was a clogged radiator, or, since it is new, insufficient capacity, as I've seen these symptoms a couple of times.
Then I saw you've removed the t'stat.

So here's a couple of ideas to try (along with all the other suggestions):
Find an old t'stat & remove the bellows & rod - you'll be left with a big washer with a hole in it - re-install it - this will restrict the water flow somewhat, but also provide some needed back pressure for the pump to work against. Think of a garden hose without or with a nozzle on the end. Your bubbles in the glass tube might speed up.
Could you temporarily install a non-curatorially-correct electric (Kenlowe?) fan? Whether it goes before or after the rad doesn't matter, as long as you know which way round it is - this might prove out the air-flow theory.

I don't know if you can test this, but what happens at speed? Imagine steady driving on a deserted motorway at 50mph - let's say all is well. Go to 60 & it overheats; drop back to 50 & it quickly cools down. This is the same but opposite (!) of overheating at idle. Edited to add: this checks out the clogged/small rad theory.

Try the t'stat first - it's cheap & can't make it any worse!
_________________
Mike - MVPeters at comcast.net
2002 MINI Cooper 'S'

[ka]

Removing a thermostat does not cure the overheating problem but just introduce lots more, if an engine does not reach its' operating temperature then they will always run rough and never evaporate the condensation forming in the engine.
Your overheating problems seem to be more fundamental, ie water pump, engine furring in water passage-ways, insufficient cooing capacity (too small a radiator), at slow running speeds an inadequate fan.
As an easy/quick fix add a wetting agent to the water, lots advertised and there was a thread on this matter earlier this year, can anyone provide a quick link?
_________________
KA

Better three than four.

[shell27]

Good morning gentlemen.
In answer to the first question, unscientific question. The fan idea may be a good one but I dont have one where I am in London we have no need of cooling fans as it does not get hot very often but I shall try and find one and check this idea. Not sure what is meant by Pressure V Boiling, as for bubbles, I could not see what they were, this just gave the indication that the water was moving, the other question is the gauge wrong well I can tell you I have a temp infrared gun and the whole engine block head and radiator are around the same temp, when the gauge on the dash shows 90 degrees so does the infrared gun.
Second question, the bypass pipe is quite big 28mm ID and I can confirm i renewed it yesterday so all clear.

[Phil - Nottingham]

Water wetter additive works well if the block is clean and not silted up as it assists heat transfer
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Rover P2
Rover P4
Rover P5 & P5B
Land Rover S2 & S3
Morris Mini Traveller Mk2

[shell27]

Morning MV
Your comments make sense, I took out the thermostat at first because it was overheating and when I got it out it looked as if it had never worked and I had to take a hammer to it to get it out rusted right in, I am not sure whether I will be able to find one anywhere as they are very rare. I am in the process of purchasing a Kenlowe to put on the front or behind not sure yet as I dont have a lot of room behind the grill or in the engine bay. Today I have removed the fan completely so it has no fan on and I am going to start it this morning to see how long it takes to get up to temp this will tell me if the fan is doing anything or not, normally with fan on around 15 minutes of idling is sufficient, I will advise.

Thanks for all the support on this one lads.

Steve

[shell27]

Hio Phil

Tried Wetter water did not seem to have an effect. I did think of that other stuff I forget what its called but you flush out the engine completely and add this product and it takes the place of water, I am reluctant to do this as it is quite costly and I might have to lose it to fix something else.
Thanks for the input.
Steve

[shell27]

MV Peter

I forgot to mention if the car is travelling along a freeway or motorway at 30mph everything is fine, I can go up to 70mph and still fine (70/80 degrees) but as soon as the car sniffs a traffic jam of any type it starts to get hot, of course it is better in the winter but really bad in the summer months
Steve

[peter scott]

[47Jag]

Steve,

You can easily test the thermostat by placing it in a pan of water and heating gradually. Ideally you would have a thermometer in the water too so that you can see what temperature the T/stat starts to open (if at all). You can get a laser thermometer for not a lot of money nowadays.

Art

[shell27]

Yes Peter I did completely miss the point, I see what you are saying now. My Thermostat sits right on top of the head and a massive top hose approx size 80mm and then reduces down to 50mm and fits on top of the Radiator. Where the housing is the bypass is just underneath where the thermostat would sit and it is quite a big bypass hose, you are saying reduce the size of bypass by clamping and that should send 80% of the water through the Radiator. I will try and see how I post a photo on this website to show you what I mean.
Steve

[shell27]

I took the thermostat out sometime ago, I will look in to getting a new one.
Steve

[Peter_L]

We haven't discussed water pressure yet. What is the setup. ?

To recap on the thermostat, I read that it was destroyed during removal


and replacements are not prolific.

Re bubbles in the water. The lower the pressure the lower the boiling point. Boiling water contains gas bubbles. Bubbles don't take the heat away from whatever they are in contact with.

The fact that the thermostat was so hard to remove makes me wonder about the free flow of water elsewhere in the system. (Already mentioned)


There is a thread on here for posting photos. It is actually easier than the instructions appear. I use Photobucket but am getting a little frustrated with the time it takes to process commands... (another topic, I don't wish to push this thread away as it contains some valuable and practical analysis)

[MVPeters]

[Farmer John]

Shell27.
Hello. There is only one symptom which is significant at present.
The bubbles in the top hose.
Whatever else might be wrong you must eliminate the bubbles, totally.
There are further tests which can be performed to ascertain their origin, unfortunately it is hard to be definite and usually results in a "best guess". Just ask if you want help there.
My opinion, which is worth exactly what it cost you, is to add a cooling system sealer. I mean a good one, that you would buy from somewhere they fix hard-working equipment.
Even one tiny bubble per minute is too much.
I suspect there is more than one fault in your car, but it has been ongoing so some effort is justified. Woops, another opinion!

John

[shell27]

We have a thread from a Farmer John who thinks the bubbles are important and feels I should find out there origin well I would not even no where to start looking. By the way John feel free to get involved as put your point over you will not offend, I have had this problem for years now and it is making the pleasure of going out in the car more and more of a chore.

Today I have purchased a domestic electric fan 450mm wide and at the same time clamped the bypass hose because Peter another member said I could be sending more water to the radiator than it can cope with. I started the engine and it run fine and also slowed down the time it takes to get to 90 degrees, so fan and clamp has helped. Tomorrow morning I am going to see what happens if I clamp only and wait for the temp to get high and then later in the day take the clamp off and just try the fan.
I am going to get a thermostat once the holidays are over also a Kenlowe and see what happens then.
Cheers Steve