Running temps, Australian 409

[MYTA21]

At a time when those with Bristol cars in Australia are reading reports about the snow in the UK, but facing temperatures approaching 40C in South Australia, perhaps I can ask what engine running temperatures are the norm for 409's in high ambient temps?
In the cooler months, the car has run about the 80-85 C mark, but in today's
35C ambient, it was running about 10c degrees higher. Fans were on very quickly and the switching on of the heater took the temperature down a noticable amount,as is usual. ( Good way of losing weight!)
I am tempted to have the radiator checked over, before we take a long trip to Victoria. I have done the usual flushing and cleaning. Any specific advice from Australian owners ref possible recoring? I have heard of some rads being worse after such work.
Thanks
Mike O

[Kevin H]

Mike, is that temp while driving along?

Is it able to hold the temp at 90-95 deg C when the car is stationary? (without the heater on!)

What pressure filler cap are you running ?

If it definitely doesn't keep getting hotter you are probably okay, although whether you are comfortable with that is a different matter. Personally I hate driving a car when I have to constantly look at the temp gauge.

A couple of things you could try - is there room to mount another electric fan on the back of the radiator? (to pull air through)

And/or you could fit a separate oil cooler.

Just my personal view, but if you decide to go down the re-core route I wouldn't bother with a straight re-core, I would replace the rad with something thicker with greater cooling capacity. I need to do that with my 411.

Regards,
Kevin

PS. They're forecasting 43 deg C for Melbourne tomorrow!

[Nick Challacombe]

The running temp for the 409 should be between 90 and 100c.
The pressure cap 15lbs
The antifreeze 25% at a minimum.

Nick

[412usa]

Please check the radiator cap, as well as the pressure cap on the expansion
tank. This proved to be the weak link when my 412 was overheating. If the
radiator cap cannot make a perfect seal then you will never achieve the 15
psi the system runs at.
Peter

[MYTA21]

Thanks for all the help on the cooling matter. In 42C yesterday, with a
brisk drive that included uphill, the gauge just got to under the 100
marker, but no sign or sounds of the of gurgling you can get and at
tickover, no noticable rise over that. Few people were out in modern cars
here yesterday!
I will look at the webosite for the other items.
Has anyone used the new Liquid intelligence coolant? I know it has a boiling
point of 190C and just allowing the engine to get hotter than it's intended
range is not a good thing. No price given on any of their data.
Thanks
Mike O

[John Keighley]

Mike,
Despite being in the Monaro region, we do experience temperatures that can challenge the older cars at times (today's temp 41C - tomorrow hotter). I generally find that our 410 temp ranges around 80 - 85. Driving around town sees this go up to 90 but switching on the fans keeps it at around 85-90 in summer.
The radiator and engine block have had extensive flushing and for a while the cooling system had a sock because the car was inactive for so long.
In this weather, I must admit that I retreat to our modern and air conditioning although I am beginning to think about A/C for the Bristol
John Keighley.

[MYTA21]

Thanks John,
I'll get the rad checked and look at higher grade core. I've been looking at
air con too!
I also priced the Liquid Intelligence coolant as a thought - $18 per litre +
GST
BR
Mike

[Hydroglen]

When you switched on the heater, you added another radiator! It can be
deducted that you main radiator is not providing enough cooling and I would
have it taken out and checked. Sometimes it is as easy as having the top
unsoldered and mechanically cleaning out the tubes.
Dorien

[MYTA21]

Thanks Dorien, Yes I think a simple check first as I've heard of recores
going wrong.
As you say the heater does act as another radiator. When you've got two
Alvis 3 litres, you know of the problems as regards heat. They have a poor
flow through the back of the head and block area.
BR
Mike

[GREG]

Change the thermostat and flush the system using rad flush, Put a hosepipe on both sides of the heater matrix and flush through. If that fails recore the original rad. Just done all the above last summer for my 408 and it doesn't move above 85 now even when stationary in a long taffic jam. And don't forget good quality anti freeze. I think that a lack of antifreeze had caused the gumming up of my rad -- previous owner. Good luck. Greg

p.s. I have spare original fans in the shroud if you need one, but I heard that the pair from a peogeot 407 diesel work great

[MYTA21]

Thanks Greg,
I'm on to that shortly.
BR
Mike

[MYTA21]

I havenow completed my cooling system work on the 409. Radiator was removed and dismantled, with some blocking noted, but repairer said core was of top quality and servicable.
New thermostat fitted.
Present Kenlowe fans changed to locally available here in Australia, David Craig ones. I had put a new motor ( MGB) on one fan, but the shrouds were rickety and the new fans fit closer to the radiator. Fan switch was questionable, so ordered one from BCL at 49 GBP + VAT if applicable.
Item is actually SU part number C 18559 for reference.
All refilled again, then flushed after trip and refilled with coolant.
I did notice that when the fans are on, there is a passage of air out of the gap between top of the radiator and front cover plate, so I am putting in a plastic piece across, so as to maximise air flow through radiator.
Then, hopefully, it's Victoria's RACV "Fly The Flag Rally" here we come.
Mike O

[Kevin H]

Mike, have you done away with the fan shroud and mounted the new fans directly against the radiator? (any pictures?)

I have added an extra fan to the back of my rad to pull air through - there are two pushing from the front.

Initially I thought it had done the job, because I sat watching the temp gauge and the fans kicked in at 75 degrees C and brought the temp down and the fans turned off again. Previously the temp would just keep going.

However, after the car had been sitting running for half an hour and I switched on the air con them temp kept rising to over 90. I turned off at that point because being a new engine I don't want to cook it.

It's still not registered (still have oil leaks which would fail the roadworthy) but I might get another unreg vehicle permit today and take it for a decent run over the weekend and see what happens. I'm fairly sure it won't overheat when it's moving, but it's when it gets stuck in traffic that worries me.

Kevin

[MYTA21]

Hello Kevin,

The two new fans from Davis Craig are mounted close up to the radiator on
the front face.
None of the Bristol/Kenlowe shroud is fitted. The arrangement gives lot more
space and visibility/
I might be able to get some photos shortly. They were mounted on with with
alloy brackets made up locally. Standard option is to use the long thin
bolts that pass through the fins, but the gap on the Bristol rad is pretty
small.
The chap who offered to do my air con says he would be fitting them on the
engine side of the rad, but it would be no great job to get this changed if
I go to air con.
Before the rad clean out, the fan switch came in around the 85C mark, but
tended to cut in and out a lot. After the rad clean out, the fan switch
appeared to operate from cold! Therefore, I bought a new one from BCL. I
would say it comes in at 85-90. Car will rise to 90 if left to idle for
length of time, but not go above that.

BR
Mike

[Bellerophon]

Kevin, It is not a good idea to let your car sit with the engine running
for half an hour, this will not do the engine any good as you need the higher
revs, to fling oil up the bores. The higher revs, of the engine is the
only way you can lubricate the bores, so take it for a drive.
My regards,
Bellerophon

[pasini s]

Hello Mike,

I have exactly the same problem on my 409 with the fans kicking in from a
very cold temperature after I had the radiators (heater+engine) recored. I
would like to buy the switch you mention, where did you buy it? Original
Otters are not available at the moment, it seems. But now the car runs very
cool (max 80°c on the highway) even with the fans disconnected; I switch
them on manually in dense traffic.

Thanks

Stefano

[MYTA21]

Hello Stefano
A pleasure to possibly help with a a posting actually on a techinical issue
of our cars!
The switch from Bristol Cars was sent out quickly 907-1-20230 c/w gasket. It
was bagged in an SU packet part numbered C18559. Small label reads LONG TYPE
OFF 80C ON 90C
Cost was 48.86 GBP, exc tax
In addition to the supply from BCL, I noted that the SU Carb agents in the
UK list the switch at 30 GBP and you might get it locally from an SU agent,
such as MIDEL, here in Australia. However, I am not advocating buying parts
from other suppliers, as BCL do provide the service on a wide range of items
and items arrive here in Australia from the UK in about a week.
I think my switch was becoming faulty before the radiator was dismantled
and possibly the heat in the area when the header tank was removed just
finished it off.
BR
Mike O

[Kevin H]

I believe Otter went out of business long ago.

I have an adjustable temperature switch on my car, which uses a temp probe inserted into the top radiator hose. I think the switch is a Kenlowe item.

The switch is mounted under the cover with the the Bristol factory ID plate that sits over the fans.

Kevin

[MYTA21]

Yes, I have the same arrangement on the Alvis - a thin copper wire looking
device that needs a special neoprene(?) slip which surrounds the copper
and fits between the hose and the rad outlet.
They can leak - I use two clips!
BR
Mike

[Kevin H]

Originally Posted by Bellerophon

Kevin, It is not a good idea to let your car sit with the engine running for half an hour, this will not do the engine any good as you need the higher revs, to fling oil up the bores. The higher revs, of the engine is the only way you can lubricate the bores, so take it for a drive.

Thanks for the advice Alan.

What about when people get stuck in traffic jams? I know you can turn the engine off, but if it's 35 degrees C outside you need to run the engine to keep the air con running.

Part of my problem at the moment is the car is not registered because it won't pass the roadworthy inspection due to oil leaks (from a brand new engine!), so I can't legally take if for a drive without an unregistered vehicle permit.

It did have an outing yesterday on such a permit and our "test drive" happened to include a visit to the RACV-AOMC Classic Showcase for British and European Cars here in Melbourne.

It behaved very well, with the temp not rising above 90, although it is clear that running the air con does raise the temperature, even on a relatively cool day (22 deg C).

A friend was following me (in an Atom) and he said he could easily see a "heat plume" from my car when it was stationary!

Unfortunately is is also still spewing out oil from at least two places, and is also leaking transmission fluid.

Regards,
Kevin