I cannot say for sure where the leak is coming from. Just took
delivery of the car. No external leaks apparent at full operating
temperature after a 22 mile drive. Temp gauge stayed within the normal
range except for towards the end of the drive getting into the "H"
zone, the idiot light came on, but then shortly after the temperature
gauge returned to normal. Both cooling fans observed working later at
idle. Bubbling occurs in the coolant reservoir.
Tried bleeding it off at the fitting where the upper radiator hose goes
into the engine to no avail. Sometimes the heater blows hot air,
sometimes cooler air. No abnormal heat coming from engine department,
and can't smell coolant at tailpipe. Do the thermostats screw up?
Sure hope its the intake gasket !
Mike Marlow wrote:
Sounds like coolant problems. You still don't say what engine, or how many
miles on the car. If it's the Series II 3.8L then it's likely the plenum is
shot. You will not likely smell coolant at the tailpipe or see white smoke.
If the car has over 40,000 miles on it you're a likely candidate for a
plenum and intake gaskets - both upper and lower. The plenum is a bit
pricey - in the neighborhood of $200. The intake gaskets are around
$40 -$80 with valve cover gaskets, depending on where you live. Can't say
what labor would be since I do all my own work. Seems to me I've heard of
these jobs going for $600-$800 for parts and labor.
It's not a bad job for a DIY'er if you've had a pretty good experience
level, working on your cars. The book pays 5 or 6 hours I believe, but you
will not likely do it that fast the first time. 3 - 4 hours is probably the
average for a guy that's done a couple. I did a set in 30 minutes or so,
but the engine was out of the car. Doesn't count - I just like to brag that
I did the job that fast. I'm married, so I don't get to brag about much...
The 3.1 is known for intake gasket failures. Check your engine oil for
coolant. The oil will be a light tan color with coolant in it, looks just
like coffee with cream. I haven't seen the head gaskets fail yet on a 3.1
but if you drive it long enough with it low on coolant you may blow a head
With a bad intake gasket, can that also make the coolant reservoir
bubble? The previous owner said he had changed oil with Wal-Mart oil,
which is clear. Looking at the oil, it looked to me like Pennzoil or
Quaker State color, so perhaps this explains the color, and, it is
about a pint overfull.
No. The bubbles are coming from pressurized gas escaping from
somewhere. Failed intake gaskets can contribute to a failed head
gasket and other mechanical problems though.
A head gasket leaking combustion gasses into the cylinder will
not always manifest itself via contaminated oil.
The correct diagnostic procedure here to rule out or verify a
leaking head gasket is to perform a cylinder leak down test;
Remove spark plugs, bring a cylinder to top dead center with the
valves closed, install leak down tester into the spark plug hole,
pressurize cylinder with compressed air, look for air bubbles in
the coolant tank or radiator fill neck. Repeat on all cylinders
until the leaking cylinder is identified or all cylinders are
Start with the rear bank of cylinders since odds are that this is
where the leak would be because (IME) the rear head gasket fails
more often than the front.
3.1 engines _do_ suffer failed head gaskets.
Last time I had an engine with that many miles and a head gasket
problem, I pulled the engine, had it bored, had the crank checked,
had the heads done, put it all back together with felpro gaskets.
That is the way to do it once and right.
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