In this summer heat the temp indicator needle will get up
above the N with just a short drive downtown and several quick
stops. The auxiliary fan kicks but still runs hotter than it
should…
Any suggestions for temporary fix short of a new radiator?
Is it wise or difficult to pull it and clean between
condenser and radiator?
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Stuck thermostat?
Regards Robin O’Connor
'92 XJ40 4.0 Ltr
Auckland NZ----- Original Message -----
From: “bgrass” bghi@comcast.net
To: xj40@jag-lovers.org
Sent: Saturday, June 30, 2012 8:57 AM
Subject: [xj40] engine runs hot
In this summer heat the temp indicator needle will get up
above the N with just a short drive downtown and several quick
stops. The auxiliary fan kicks but still runs hotter than it
should…
Any suggestions for temporary fix short of a new radiator?
Is it wise or difficult to pull it and clean between
condenser and radiator?
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting
services and resources including Photo Albums, Event Diary / Calendar, On
Line Books and more !
Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !
In reply to a message from bgrass sent Fri 29 Jun 2012:
Bryan,
It is fairly easy to remove the top radiator/ condenser
plate and peer down in to the void between the two. I fitted
a narrow tube on to a vacuum cleaner nozzle to suck some of
the debris out, but a lot of it consisted of short lengths
of straw and grass which were caught in the radiator or
condenser matrices and I used one of those
flexible/extendable claw devices to pluck stuff out.
Tape a couple of extensions to the handles of a pair of
pliers so you can reach down and grab stuff.
Worth doing - but are you sure that your water pump is
working OK.
I recall someone on this forum experiencing a slipping
pulley on the water pump shaft. The pulley is not keyed on
to the shaft, just a push (interference) fit and on his car
it was spinning without turning the water pump impeller 100%.–
The original message included these comments:
In this summer heat the temp indicator needle will get up
above the N with just a short drive downtown and several quick
stops. The auxiliary fan kicks but still runs hotter than it
should…
Any suggestions for temporary fix short of a new radiator?
Is it wise or difficult to pull it and clean between
condenser and radiator?
p.S. planning a 870 mile drive this Sunday!!
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In reply to a message from Bryan N sent Fri 29 Jun 2012:
I have pulled the top plate as you suggested and can see some
debris and will clean that out but doesn’t look too bad… I
can spin the fan blade about 3/4 turn which I understand is
normal, would that be the test for the water pump too?
About 3 weeks ago I drove the same trip over 800 miles, and as
long as I was on the highway it stayed normal.
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In reply to a message from bgrass sent Fri 29 Jun 2012:
on the highway, you have air rushing through the grill etc and
under the car, so the temperature will stay down.
i m not sure what the stats are, perhaps bryan n. may know, but
here in the u.k, we can buy what we call winter and summer
thermostats, or at least you could at one time. if they are
available, perhaps it maybe worth buying one that opens at a lower
temperature. I know some parts of the states are getting 110
degrees at the moment, which is nt good for anyone, especially
engines!!
i m not sure if you can do it with these cars, but years ago I
remember taking the stat out altogether in the summer!
as said though, debris between rads is possible, faulty pump/stat
and also make sure the rubber flaps on the shroud work right and
close. apparently this can affect air circulation.–
The original message included these comments:
About 3 weeks ago I drove the same trip over 800 miles, and as
long as I was on the highway it stayed normal.
Thanks…
bgrass
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In reply to a message from 4.0sovereign sent Fri 29 Jun 2012:
Thanks for advice…It was 107 degrees here today, OUCH!!
Yes those lower temp rated thermostats are available. I was
also told by a mechanic that I could pull the existing stat
and drill two small holes in the lip of t-stat to help
release pressure.
I did get a bottle of super coolant by lucus that the auto
parts person said is good on these older cars, and we are
driving thru the night instead heat of the day.–
bgrass
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In reply to a message from bgrass sent Fri 29 Jun 2012:
Most newer cars need some sort of thermostat to allow the engine to
run at a temp that will allow sensors to perform properly. Engine
controls depend on engine temps for rich or lean fuel mixtures and
removing a stat may cause problems. Brandon.–
Brandon St James X308 2002 VDP 4.0L
VENTURA CALIFORNIA, United States
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In reply to a message from bgrass sent Fri 29 Jun 2012:
The viscous coupling on the fan sounds as if it is working
correctly - and therein lies a problem in trying to detect
‘slippage’ of the pulley on the water pump shaft - no way of
telling since it is not a ‘hard’ connection. The only way
you would tell is to remove the pump, hold the impeller and
try to turn the pulley by hand. However, that problem must
be such a rare occurrence (since I can only recall one
isolated example) that I would look for other solutions first.
When did you last drain and flush the radiator and cooling
system?
BTW, on my car at ambient temperatures way below 107� F,
if in the middle of a journey I stop for fuel or food, when
I return to the car after a few minutes and start the
engine, the needle on the temperature gauge always registers
a few degrees above the ‘N’ on the dial whereas it normally
sits dead centre of the ‘N’ under all driving conditions
whatever the ambient temperature. It then takes quite a few
miles of driving before the needle again drops to its normal
central position, even with the auxiliary electric fan running.
My car has the genuine Jaguar (i.e expensive!) OEM
thermostat - does yours?–
The original message included these comments:
I have pulled the top plate as you suggested and can see some
debris and will clean that out but doesn’t look too bad… I
can spin the fan blade about 3/4 turn which I understand is
normal, would that be the test for the water pump too?
About 3 weeks ago I drove the same trip over 800 miles, and as
long as I was on the highway it stayed normal.
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In reply to a message from Bryan N sent Sat 30 Jun 2012:
Bryan,
The way you described the behavior of your car is pretty much
like mine. I Don’t know about the genuine jag stat in mine but
I did pull it last week and it was fine (it has the little
slip-tab which I made sure was on top when I reinstalled).
The auto parts showed they can get deferent temperature t-stat
with lower or higher temp ratings.–
bgrass
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