[Nobbc] Xk 120 over heating

Mon Jul 28 18:02:48 MDT 2008

Hello Charlie - My gosh! before you add fans, an oil cooler, or have an
overhaul, consider this: Your Jag  was not designed to overheat; altho it was
for a cooler climate and shorter runs than we do in CA. All mechanics in the
car being good, it should not overheat and coolers and fans will not fix the
real problem, whatever it is.

I don't know what you mean by overheat. Does it reach 220, 240? Does it "boil
over", hence the overflow tank? Does it blow steam like the Edinbrough
Express?

First things to check are: coolent level, slipping fanbelt, defective water
pump, sticking/closed thermosat, rust and scale clogging the system, airflow
through rad, external leaks.

If these elements are right, then start thinking about hot gases getting into
the coolent through an internal leak.

Thermstat check is easy: let it idle and watch the temp gauge. it should rise
to as much as 200 and then drop back to 160 or 180 (whatever your thermstat
is). You can put your hand on the top hose and feel the warm coolent flow when
it opens.

When was the last time you flushed and changed coolent in the rad? (Always run
50/50 coolent and distilled h2o). Just a few tubes obstructed can cause a loss
of cooling.

Do a pressure check on the system. Pump it up to 15psi and see if it leaks
down.(Napa has this tool.) Yes? look for external leaks - hoses. No? Maybe an
internal leak, but let a pro test for it,(you could scald yourself.)

Any water bubbles on the dip stick?

Have you had to fill the system lately? When filling a cooling system, it is
usually necessary to "burp" the system as air pockets can cause problems.
Again, this can burn you if you don't know what you are doing.

Too much retard and lean carbs, as someone else said, can contribute to
heating, but I think you would have been concerned about poor running. It is
always good to frequently check timing, dwell and carb mixture. (part of the
fun of our old girls is fussing with them.)

I am not an automotive engineer, but these comments come from 55 years of
working on Brit cars and 15 for a livelyhood.

Although I don't think I have suggested anything whereby you can hurt
yourself, I just need to remind you that hot cooling systems under pressure
are very dangerous and can cause you severe injury. Be careful. I don't know
what your experience is.

BTW, overflow bottles are a good addition and will help to preserve the
environment, drip by drip.

Robin

  From: Charlie Saul<mailto:csaul at noleak.com>
  To: North Bay British Car Club<mailto:nobbc at autox.team.net>
  Sent: Monday, July 28, 2008 9:12 AM
  Subject: Re: [Nobbc] Xk 120 over heating

  Thanks so much Dick,

  I'll be sure to have the advance checked.

  Hope to be cool running soon!

  Charlie

  -----Original Message-----
  From: nobbc-bounces at autox.team.net<mailto:nobbc-bounces at autox.team.net>
[mailto:nobbc-bounces at autox.team.net]
  On Behalf Of Richard Anderon
  Sent: Monday, July 28, 2008 7:34 AM
  To: North Bay British Car Club
  Subject: Re: [Nobbc] Xk 120 over heating

  Hi Charlie,  I have a '67 XKE and agree with Dawson on both.
  Hopefully the raised bottle will help.  If needed, fan kits with shroud
  are available from most Jag parts houses.  Mine runs cool and have found
  that the tune of the engine helps that.  Don't be to lean and check the
  advance.

  Dick
  On Jul 27, 2008, at 5:28 PM, Charlie Saul wrote:

  > Hi Dawson,
  >
  > You got it; the bottle is mounted too low. Great suggestions; will
  > check it out!
  >
  > Thanks a bunch,
  >
  > Charlie
  >
  > -----Original Message-----
  > From: nobbc-bounces at autox.team.net<mailto:nobbc-bounces at autox.team.net>
  > [mailto:nobbc-bounces at autox.team.net
  > ]
  > On Behalf Of Dawson Church
  > Sent: Saturday, July 26, 2008 9:47 PM
  > To: North Bay British Car Club
  > Subject: Re: [Nobbc] Xk 120 over heating
  >
  > Are you sure your radiator overflow bottle is ABOVE the level of the
  > radiator. I had a mechanic "helpfully" install one in my Lotus, it was

  > BELOW, and drained water from the radiator when hot!
  >
  > I solved the overheating problem in my 2 Lotuses by installing
  > electric fans that come on a low temperature. Torqueflow brand,
  > installs in about an hour, sold at Autozone, turned on by a sensor
  > that goes through the radiator fins. You MUST get a sensor that
  > triggers at low temperature, the regular ones trigger too high, the
  > engine is already cooking before they signal the fans to turn on.
  >
  > Dawson
  >
  >
  > On Jul 26, 2008, at 7:06 PM, Charlie Saul wrote:
  >
  >> Hi All:
  >>
  >> Trying to get my xk 120 back on the road:
  >> I installed a radiator overflow bottle and it overflows a lot when I
  >> drive for 15 minutes and turn the car off.
  >> One mechanic says car is overheating due to rings, valves, head
  >> gasket
  >
  >> etc.; car engine needs to be overhauled.
  >> Another mechanic says that since I likely will drive the car less
  >> than
  >
  >> 1000 miles a year, I should just have an oil cooler installed.
  >> Will this bring the temp down significantly?
  >>
  >> Regards,
  >>
  >> Charlie
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