Toyota Trucks: yikes- it's COLD and my coolant system is doing strange things!

"Joa" <com> wrote in message
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That's pretty suspicious. Do you have a coolant tester? You can buy one for
a few bucks at a parts store. See if your coolant has the proper specific
gravity. (The cheap testers don't actually tell you the s.g., they just give
you an estimated freeze/boil point, which is fine.)

My first suspicion, if I had this vehicle in my driveway, would be that the
freezing point of the coolant is too high and it is partially freezing and
blocking the coolant circulating system. It eventually is remedied when the
engine gets hot enough to melt the block. It'd be my first suspicion because
it's the easiest and cheapest to test and to fix. If it's the coolant,
partially drain it and add straight a/f or a mix, depending on how bad the
tester says the problem is.

Then there's the question of *why* the coolant was bad. Again, my first
guess, because it's the sort of thing I'd do if I wasn't paying attention,
would be that you bought premix a/f and cut it with water as if it were
straight. If you still have the bottle, just check it. If that's the
problem, have a hearty laugh and go forth and sin no more. Another
possibility is that you got bad a/f.

After that, it gets bad. Thermostat not functioning properly? Corrosion
loosened by flush and fill blocking circulation? Leak in system (possibly
caused by contraction of something in extreme cold) not allowing proper
pressurization or letting water in somehow? Water pump sticking? Dunno. I
just do the easy stuff.

D

Joa wrote:
 

Same temps here, but mine is doing fine (it also got a flush, t-stat,
and other bits this fall) so far.
 

First thought is stuck t-stat.
 

Low coolant level combined with stuck t-stat? If the water was hot,
there should have been spillover.
 

That seems to go with stuck t-stat. If you bought an after-market
t-stat, it may not have been the correct t-stat. Toyota uses a 2-state
t-stat.
 

This can also point to a blown head gasket: no heat, over-heating
engine. If you drive a vehicle and overheat it enough times, you can
end up damaging the head gasket(s).

 

Warm, or hot? If it is a two-stage, or an aftermarket with a "hole" in
it, it can allow some flow, which would be perceived as "warm." It
should be _hot_.
 

This is absolutely no good. Coolant in the resevoir should be fluid at
temps to usually -35F, standard mix. Test your coolant mix (both in the
rad and the resevoir) with a known good tester.
 

Especially with the mileage, I'd consider the possibility that the head
gasket(s) have blown, due either to wear, frozen coolant lines from low
coolant mix, or overheat due to blocked t-stat/failing water pump.

With the truck warm, pull the oil-fill cap. Look for steam rising from
the head, or some "milkshake" on the underside of the cap.

good luck!
GTr
'89 V6 4x4 DLX 198k (amongst others)

The same thing happened to me with my old honda civic many years back. One
frigid morning the temperatures turned frigid and I had no heat for a 50
mile drive to work. After letting it sit for 4 hrs or so ( as the sun came
up ) I started the motor and the heat started working as normal. The same
thing happened over the next several days while the temperature was still
frigid. Then one day while heading to work the temperature gauge began to
rise when I hit heavy traffic. I pulled over and sat there for 30 min or so.
Started her up and drove normally but the temp gauge was consistantly much
higher than normal. For the next couple of days the motor was very prone to
overheat.

Well the problem ended up being a partially plugged radiator. Apparantly,
the frigid temperature was what brought it on .I had added some "bars stop
leak" pellets a year earlier and this contributed to the plugging. A new
radiator fixed it and everything was normal.
"Joa" <com> wrote in message
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