Bad oil pump??

My '92 Miata with about 90K, has been pegging the oil pressure gauge at the
90 psi mark during acceleration. Thinking it was the gauge or sending unit,
I took it to my mechanix. He said the both were fine and the oil pressure
was actually in the 70-90 psi range at 2500-3000 rpm. He said the oil
relief valve in the oil pump has failed and a new pump is required at huge
$$$. A big labor job...

Is this possible?? Any way to find out without the big $$?
All input is welcome. Thoughts.
Thanks!

Solara wrote:
> He said the oil
> relief valve in the oil pump has failed and a new pump is required at
huge
> $$$. A big labor job...
>
> Is this possible?? Any way to find out without the big $$?

Sounds plausible to me. Mine's a 94, but the shop manual for it says
the oil relief valve is designed to kick in between 50 and 63 psi.

The danger with your high pressure is that it could blow out the filter
element in your oil filter and send it and all the crud thru your
engine.

Hope I'm wrong, but it does sound like big bucks. Might be cheaper to
buy a used engine in known good condition than to spend the labor to
rebuild the one you have. Engine usually has to come out to change the
pump - unless your mechanic is really good.

This happened to a friend of mine. Before you spring for a new pump, think
about adding about a quart of Rislone or a similar product, making sure that
you do not overfill. Next, with a new filter( pre lube it with the oil
mixture, start and run a few minutes, watching the oil pressure and engine
temperature.) It may take several cycles of this, with cool down between
(allows the solvent to work) to clear the muck from the system. Another
additive that has a similar effect is about the same amount of automatic
tranny fluid. We always used a straight grade oil with either solvent.
If you manage to clear the problem, go to a recommended oil and change it
more frequently than was done in the past.
It's possible that the problem is also related to the brand and type of oil
used.

> wrote in message
oups.com...
> Solara wrote:
>> He said the oil
>> relief valve in the oil pump has failed and a new pump is required at
> huge
>> $$$. A big labor job...
>>
>> Is this possible?? Any way to find out without the big $$?
>
> Sounds plausible to me. Mine's a 94, but the shop manual for it says
> the oil relief valve is designed to kick in between 50 and 63 psi.
>
> The danger with your high pressure is that it could blow out the filter
> element in your oil filter and send it and all the crud thru your
> engine.
>
> Hope I'm wrong, but it does sound like big bucks. Might be cheaper to
> buy a used engine in known good condition than to spend the labor to
> rebuild the one you have. Engine usually has to come out to change the
> pump - unless your mechanic is really good.
>


---
Outgoing mail is AVG certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.806 / Virus Database: 548 - Release Date: 12/5/2004

Thanks for the suggestion. I have the car at another shop today for a 2nd
opinion. I watched the gauge very closely as we drove this weekend, and it
does start out getting at or near 90 psi with the engine cold, but within
2-3 minutes as the motor warms up, the pressure begins to hang out at or
below 60 psi, and I can see the relief valve working as I run up the
RPM's. Appears the pressure climbs until about 62-65 psi, as RPM increase,
then at about 2500-2700rpm, the pressure drops back to slightly under 60
and pretty much holds there as we drove. At idle, I have about 30 psi,
again, all on the car gauge. I'll update this message tonight. Thanks to
all who posted.

In article
outautos.com>,
"Solara" > wrote:

> I watched the gauge very closely as we drove this weekend, and it
> does start out getting at or near 90 psi with the engine cold, but within
> 2-3 minutes as the motor warms up, the pressure begins to hang out at or
> below 60 psi, and I can see the relief valve working as I run up the
> RPM's. Appears the pressure climbs until about 62-65 psi, as RPM increase,
> then at about 2500-2700rpm, the pressure drops back to slightly under 60
> and pretty much holds there as we drove. At idle, I have about 30 psi,
> again, all on the car gauge.

You've just described the normal operation of a healthy Miata engine
with a real oil pressure gauge. Stop worrying.

--
Lanny Chambers, St. Louis, USA
'94C
the alignment page:
http://www.hummingbirds.net/alignment.html

I'd agree, since the idle oil pressure is more or less normal. The 90 psi
(if actual) is a bit high though, unless heavy oil is used. Given the
factory oil pressure gauges, I'd want to check with an accurate gauge before
deciding to do anything.

"Lanny Chambers" > wrote in message
...
> In article
> outautos.com>,
> "Solara" > wrote:
>
>> I watched the gauge very closely as we drove this weekend, and it
>> does start out getting at or near 90 psi with the engine cold, but within
>> 2-3 minutes as the motor warms up, the pressure begins to hang out at or
>> below 60 psi, and I can see the relief valve working as I run up the
>> RPM's. Appears the pressure climbs until about 62-65 psi, as RPM
>> increase,
>> then at about 2500-2700rpm, the pressure drops back to slightly under 60
>> and pretty much holds there as we drove. At idle, I have about 30 psi,
>> again, all on the car gauge.
>
> You've just described the normal operation of a healthy Miata engine
> with a real oil pressure gauge. Stop worrying.
>
> --
> Lanny Chambers, St. Louis, USA
> '94C
> the alignment page:
> http://www.hummingbirds.net/alignment.html


---
Outgoing mail is AVG certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.806 / Virus Database: 548 - Release Date: 12/5/2004

In article >,
"chuckk" > wrote:

> The 90 psi (if actual) is a bit high though, unless heavy oil is
> used.

It's perfectly normal for 10W-30 in subfreezing weather.

--
Lanny Chambers, St. Louis, USA
'94C
the alignment page:
http://www.hummingbirds.net/alignment.html

Lanny Chambers > wrote:

>In article >,
> "chuckk" > wrote:
>
>> The 90 psi (if actual) is a bit high though, unless heavy oil is
>> used.
>
>It's perfectly normal for 10W-30 in subfreezing weather.

Yes, 90 cold is, even at idle if sufficiently cold.

But the cited numbers when the oil is fully warmed up, like 30 at
idle, seem too high. I could imagine that the mechanic who wanted
to change the $$$ oil pump, and who was apparently unaware that the
oil pressure depends on oil temperature, put in the wrong weight
of oil. If the oil pressure after say 30 minutes driving is not
well below the 30 mark, say 20, I would take the safe route and
replace the oil.

Leon


--
Leon van Dommelen Bozo, the White 96 Sebring Miata .)
http://www.dommelen.net/miata
EXIT THE INTERSTATES (Jamie Jensen)

I took it to another respected shop today and they said all was well, and
they did not recommend doing anything but driving it and having a good
time. They said you must check the pressure after engine warmup, and mine
had very normal pressure at that time, and at all RPM's. Thanks everyone
for all the input. Happy holidays!

Great Christmas present! Now, you need to make sure you never, ever, go
back to the shop that wanted to replace your oil pump unless it is to
tell them they are buffons.

Tom
92 Red

Solara wrote:
> I took it to another respected shop today and they said all was well, and
> they did not recommend doing anything but driving it and having a good
> time. They said you must check the pressure after engine warmup, and mine
> had very normal pressure at that time, and at all RPM's. Thanks everyone
> for all the input. Happy holidays!
>