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Hi,
I think I may have narrowed down an Engine overheating problem to a leaky
reservoir / overflow tank. It first manifested as A/C problems over the
last couple weeks, really. I just assumed something was wrong with the
design, where it didn't cool efficiently until you reached highway speeds,
which would be enough to cool off the Engine so you could finally get good
A/C. Finally last night the CEL comes on and honestly yesterday was the
first time I noticed the Engine temp indicator was all the way on the HOT
side, except when on the HWY it comes back to normal. I simply hadn't
noticed. This morning I did some checks I read about -- debris in rad
(can't really get rid of this without hose & water, besides being cooled
off @ high speeds means it's clean enough, IMO), coolant level (below the
low mark, I added more), and the state of the reservoir cap -- no rust,
scale, etc.
But after I drove it for about ten minutes, the temp went all the way up
again. When I came back and opened the hood, there was steam leaking from
the side of the reservoir tank.
Question, should I C&D on driving the car till I can get a replacement tank
put on? I may consider getting a rental but it'll cost me. Also, do
generics typically work in these situations or should I wait on Mazda's?
Finally, are there any other things I should be looking at? I also checked
the upper and lower radiator hose pressure / temps to eliminate the
thermostat as a cause of the problem. Lower hose was warm to the touch,
not cool, so apparently the therm isn't stuck on closed. The top hose had
some pressure and spring-back to it... I forget what this was supposed to
eliminate... oh, water pump, I think it was. Let me know if I should pay
attention to anything else. I will probably plan for a rental this morning
but hopefully not much longer! I can't open the overflow tank for another
three hours due to reaching Engine operating temp so I couldn't top off the
coolant now even if I wanted, right?
JaneiR36
Ugh. Dealer had the tank in stock. Apparently this is a common issue, the
leaky reservoir. So I replaced the thing just now and took it out on a
low-speed test drive. No more leaky from the overflow tank and the AC was
actually cold for a while there. Then it went all the way to hot, just as I
was about to do my victory dance
The lower hose I thought was warm is very much cold now. Pointing back to
the thermostat, perhaps? But why not before? Why only now? Like I said,
ugh.
JaneiR36
My first impression is the expansion tank overflow is a symptom not a cause
and that you have a knackered head gasket (you may be lucky with the
thermostat replacement). You might find high engine temps are interlocked
with the aircon operation to prevent the compressor from running.
Wally
I just might have to jump off a cliff if you're right!! The therm really
may not be it because it reports a nice low temp, until the Engine truly
reaches operation speed then it turns to hot. If it was stuck, it really
should read only one number with no rhyme or reason. Dang.
JaneiR36
P0117 Engine coolant temperature circuit low input
Does this tend to point to anything in particular? I'll have the Sears
folks look at it, buy probably not till tomorrow in case someone here is
familiar with this and it's something simple :-)
JaneiR36
Busted cooling fan relay. How embarassing! I tested the coil resistance
and it was within spec. I should have just replaced it because there so
cheap!! The dealer didn't have the relay in stock, so they replaced it with
the defrost fan relay. Quite intelligent of them!!
JaneiR36
Well done. I actually thought of that few days ago, but was too lazy to
post.
Wally
