[MR2] A high speed cooling problem

[Bob Schultz]

Did the guy use an OEM thermostat.  Toyota's don't play well with
aftermarket thermostats...
Toss on a new radiator cap just for good measure.

If he used an OEM thermostat go get yourself a block test or have someone
with a 4 gas analyzer check for hydro carbons in the overflow.
It wouldn't surprise me if you have a failing head gasket.

It isn't as big of a deal as it sounds, it takes time but it is not rocket
science to change it,  just follow the BGB.

Bob


-----Original Message-----
From: mr2-bounces at mr2.com [mailto:mr2-bounces at mr2.com] On Behalf Of
felix at crowfix.com
Sent: Friday, September 11, 2009 12:18 PM
To: mr2 at mr2.com
Subject: [MR2] A high speed cooling problem

My 86 MkI overheats, a little, on hot days on the freeway, and no
other time or place.  It maketh me nervouth.

I bought the car new, it now has 423,000 miles on it, and in all that
time, the temp gauge has always been rock solid sitting just to the
cool side of center, just enough to see the top half or so of the
white center line.  The only time it has ever been elsewhere is (1) on
start, (2) when a coolant hose broke, and (3) one time when I thought
the alternator was on its last gasp and I drove in 3rd on the freeway
for 5-10 miles.

Several months ago, on a hot California central valley day with A/C
going close to full blast, I noticed tha needle was just as far to the
warm side as it had always been on the cool side -- ie, not much, but
it had never done that before.  I slowed down some (80 to 70 or 65, I
think) and turned the A/C down to minimum, and the needle went back to
its usual position over the next mile or two.  Bummer!

I had a 60K service coming up, so the local mechanic who has been
looking after the car for the last ten yeras or so replaced the
thermostat, and when the next hot spell came around, it seemed to make
no difference.  However, it also overheated more just driving up the
dirt road to home at 5-10 miles an hour (it is pretty bumpy), rising
to halfway between normal and max, but a friend noticed that the front
license plate had been pushed back all the way and was making it hard
for the radiator fans to do any good.  Straightened it out and no more
low speed over heating.  I am a bit puzzled by this, because it seems
unlikely that this was the first time in 23 years for that to happen.

And it didn't cure the freeway overheating.  We had another few days
of 100+ and the same problem came back.  I pulled over, checked the
license plate, it was normal, and I proceded on my trip at 65 with the
A/C low, and it did not overheat again.

There's plenty of coolant.  Oil looked fine last few times I checked.
I've looked several times to se if a plastic bag or leaves have been
stuck on the radiator, but nope.  When it is on the warm side, I think
I notice within a few minutes, and I do not continue at the same speed
and A/C setting, so I don't know how steady it is there, but it isn't
rising noticeably when I do notice, so any rise must be pretty slow.
I think it has just settled down at a new point, but I have no proof.

One other thing -- sometimes there is an electrical smell coming from
the engine compartment when I get out to get gas and check the oil.
Not real strong, but enough that I notice it when peering down to put
the dipstick back in its tube (I ought to paint that sucker with glow
in the dark paint).  I do not know if I would have even noticed it if
I hadn't been worried about the overheating, so I don't know if it is
related or not.  By "electrical smell", I think I mean ozone, not the
smell of burned electronics but the smell from generators.

-- 
            ... _._. ._ ._. . _._. ._. ___ .__ ._. . .__. ._ .. ._.
     Felix Finch: scarecrow repairman & rocket surgeon / felix at crowfix.com
  GPG = E987 4493 C860 246C 3B1E  6477 7838 76E9 182E 8151 ITAR license
#4933
I've found a solution to Fermat's Last Theorem but I see I've run out of
room o

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