High Oil Pressure Reading - Sending Unit?
 

Quick question for y'all.

'99 TJ Sahara, 128K miles, no major engine repairs yet except for the
exhaust manifold. Last oil change was about a month ago, with synthetic
5W30.

We got hit with the cold today, and on the drive home from my
mother-in-law's, I saw that the oil pressure gauge was at 80. It normally
runs the 20-60 range. The engine seemed to warm up quicker than it usually
did (but then it had been driven for 2 hours on the way up, and only sat for
about 3.5 hours before we headed home). When I took off the gas, the
pressure gauge came down to 60. As we continued driving, it slowly crept
down, so by the time we got home half an hour later, it was at 60 at 2000
RPM, and 40 at idle. The engine temp stayed at 210.

Some quick research showed that this is probably the oil sending unit, but
the fact that the pressure gauge dropped over the course of the drive home
has me wondering - if it were a bad sending unit, wouldn't it have stayed at
80?

Thanks for any thoughts or recommendations.

Tirya
--
TDC Inca Jeeper
A girl and her Jeep... it's a beautiful thing...

Re: High Oil Pressure Reading - Sending Unit?
 

Tirya did pass the time by typing:
> Quick question for y'all.
>
> '99 TJ Sahara, 128K miles, no major engine repairs yet except for the
> exhaust manifold. Last oil change was about a month ago, with synthetic
> 5W30.
>
> We got hit with the cold today, and on the drive home from my
> mother-in-law's, I saw that the oil pressure gauge was at 80. It normally
> runs the 20-60 range. The engine seemed to warm up quicker than it usually
> did (but then it had been driven for 2 hours on the way up, and only sat for
> about 3.5 hours before we headed home). When I took off the gas, the
> pressure gauge came down to 60. As we continued driving, it slowly crept
> down, so by the time we got home half an hour later, it was at 60 at 2000
> RPM, and 40 at idle. The engine temp stayed at 210.
>
> Some quick research showed that this is probably the oil sending unit, but
> the fact that the pressure gauge dropped over the course of the drive home
> has me wondering - if it were a bad sending unit, wouldn't it have stayed at
> 80?

Not always. Might pull the electrical connector off the sending unit
(down by the oil filter), clean it, and put it back.
http://members.cox.net/wilsond/Fixes...r-oil-pressure

A little crud knocked loose by your switch to synthetic may also be the cause.
(If you neglected oil changes prior to this. IF you did regular changes 3,000
-4,000 miles then this probably isn't the case)


--
-- DougW -- 93 ZJ 4.0 http://members.cox.net/wilsond
HESCO Supercharger - 300W IASCA Stereo - Edelbrock IAS Shocks
Gibson Exhaust - rear DCpower - custom gauge install - Stillen Rotors
Banks Header - and BEER, in the fridge!

Re: High Oil Pressure Reading - Sending Unit?
 

Tirya did pass the time by typing:
> Quick question for y'all.
>
> '99 TJ Sahara, 128K miles, no major engine repairs yet except for the
> exhaust manifold. Last oil change was about a month ago, with synthetic
> 5W30.
>
> We got hit with the cold today, and on the drive home from my
> mother-in-law's, I saw that the oil pressure gauge was at 80. It normally
> runs the 20-60 range. The engine seemed to warm up quicker than it usually
> did (but then it had been driven for 2 hours on the way up, and only sat for
> about 3.5 hours before we headed home). When I took off the gas, the
> pressure gauge came down to 60. As we continued driving, it slowly crept
> down, so by the time we got home half an hour later, it was at 60 at 2000
> RPM, and 40 at idle. The engine temp stayed at 210.
>
> Some quick research showed that this is probably the oil sending unit, but
> the fact that the pressure gauge dropped over the course of the drive home
> has me wondering - if it were a bad sending unit, wouldn't it have stayed at
> 80?

Not always. Might pull the electrical connector off the sending unit
(down by the oil filter), clean it, and put it back.
http://members.cox.net/wilsond/Fixes...r-oil-pressure

A little crud knocked loose by your switch to synthetic may also be the cause.
(If you neglected oil changes prior to this. IF you did regular changes 3,000
-4,000 miles then this probably isn't the case)


--
-- DougW -- 93 ZJ 4.0 http://members.cox.net/wilsond
HESCO Supercharger - 300W IASCA Stereo - Edelbrock IAS Shocks
Gibson Exhaust - rear DCpower - custom gauge install - Stillen Rotors
Banks Header - and BEER, in the fridge!

Re: High Oil Pressure Reading - Sending Unit?
 

Tirya did pass the time by typing:
> Quick question for y'all.
>
> '99 TJ Sahara, 128K miles, no major engine repairs yet except for the
> exhaust manifold. Last oil change was about a month ago, with synthetic
> 5W30.
>
> We got hit with the cold today, and on the drive home from my
> mother-in-law's, I saw that the oil pressure gauge was at 80. It normally
> runs the 20-60 range. The engine seemed to warm up quicker than it usually
> did (but then it had been driven for 2 hours on the way up, and only sat for
> about 3.5 hours before we headed home). When I took off the gas, the
> pressure gauge came down to 60. As we continued driving, it slowly crept
> down, so by the time we got home half an hour later, it was at 60 at 2000
> RPM, and 40 at idle. The engine temp stayed at 210.
>
> Some quick research showed that this is probably the oil sending unit, but
> the fact that the pressure gauge dropped over the course of the drive home
> has me wondering - if it were a bad sending unit, wouldn't it have stayed at
> 80?

Not always. Might pull the electrical connector off the sending unit
(down by the oil filter), clean it, and put it back.
http://members.cox.net/wilsond/Fixes...r-oil-pressure

A little crud knocked loose by your switch to synthetic may also be the cause.
(If you neglected oil changes prior to this. IF you did regular changes 3,000
-4,000 miles then this probably isn't the case)


--
-- DougW -- 93 ZJ 4.0 http://members.cox.net/wilsond
HESCO Supercharger - 300W IASCA Stereo - Edelbrock IAS Shocks
Gibson Exhaust - rear DCpower - custom gauge install - Stillen Rotors
Banks Header - and BEER, in the fridge!

Re: High Oil Pressure Reading - Sending Unit?
 

I would be suspicious of a failed filter. If the filter fails
internally, the oil pressure spikes and the bypass valve shunts it past
the filter.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Tirya wrote:
>
> Quick question for y'all.
>
> '99 TJ Sahara, 128K miles, no major engine repairs yet except for the
> exhaust manifold. Last oil change was about a month ago, with synthetic
> 5W30.
>
> We got hit with the cold today, and on the drive home from my
> mother-in-law's, I saw that the oil pressure gauge was at 80. It normally
> runs the 20-60 range. The engine seemed to warm up quicker than it usually
> did (but then it had been driven for 2 hours on the way up, and only sat for
> about 3.5 hours before we headed home). When I took off the gas, the
> pressure gauge came down to 60. As we continued driving, it slowly crept
> down, so by the time we got home half an hour later, it was at 60 at 2000
> RPM, and 40 at idle. The engine temp stayed at 210.
>
> Some quick research showed that this is probably the oil sending unit, but
> the fact that the pressure gauge dropped over the course of the drive home
> has me wondering - if it were a bad sending unit, wouldn't it have stayed at
> 80?
>
> Thanks for any thoughts or recommendations.
>
> Tirya
> --
> TDC Inca Jeeper
> A girl and her Jeep... it's a beautiful thing...

Re: High Oil Pressure Reading - Sending Unit?
 

I would be suspicious of a failed filter. If the filter fails
internally, the oil pressure spikes and the bypass valve shunts it past
the filter.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Tirya wrote:
>
> Quick question for y'all.
>
> '99 TJ Sahara, 128K miles, no major engine repairs yet except for the
> exhaust manifold. Last oil change was about a month ago, with synthetic
> 5W30.
>
> We got hit with the cold today, and on the drive home from my
> mother-in-law's, I saw that the oil pressure gauge was at 80. It normally
> runs the 20-60 range. The engine seemed to warm up quicker than it usually
> did (but then it had been driven for 2 hours on the way up, and only sat for
> about 3.5 hours before we headed home). When I took off the gas, the
> pressure gauge came down to 60. As we continued driving, it slowly crept
> down, so by the time we got home half an hour later, it was at 60 at 2000
> RPM, and 40 at idle. The engine temp stayed at 210.
>
> Some quick research showed that this is probably the oil sending unit, but
> the fact that the pressure gauge dropped over the course of the drive home
> has me wondering - if it were a bad sending unit, wouldn't it have stayed at
> 80?
>
> Thanks for any thoughts or recommendations.
>
> Tirya
> --
> TDC Inca Jeeper
> A girl and her Jeep... it's a beautiful thing...

Re: High Oil Pressure Reading - Sending Unit?
 

I would be suspicious of a failed filter. If the filter fails
internally, the oil pressure spikes and the bypass valve shunts it past
the filter.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Tirya wrote:
>
> Quick question for y'all.
>
> '99 TJ Sahara, 128K miles, no major engine repairs yet except for the
> exhaust manifold. Last oil change was about a month ago, with synthetic
> 5W30.
>
> We got hit with the cold today, and on the drive home from my
> mother-in-law's, I saw that the oil pressure gauge was at 80. It normally
> runs the 20-60 range. The engine seemed to warm up quicker than it usually
> did (but then it had been driven for 2 hours on the way up, and only sat for
> about 3.5 hours before we headed home). When I took off the gas, the
> pressure gauge came down to 60. As we continued driving, it slowly crept
> down, so by the time we got home half an hour later, it was at 60 at 2000
> RPM, and 40 at idle. The engine temp stayed at 210.
>
> Some quick research showed that this is probably the oil sending unit, but
> the fact that the pressure gauge dropped over the course of the drive home
> has me wondering - if it were a bad sending unit, wouldn't it have stayed at
> 80?
>
> Thanks for any thoughts or recommendations.
>
> Tirya
> --
> TDC Inca Jeeper
> A girl and her Jeep... it's a beautiful thing...

Re: High Oil Pressure Reading - Sending Unit?
 

Never would have thought of that.

Mike Romain wrote:

> I would be suspicious of a failed filter. If the filter fails
> internally, the oil pressure spikes and the bypass valve shunts it past
> the filter.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>

--
__________________________________________________ _________
tw

71 Bill Stroppe Baja Bronco
03 TJ Rubicon - Rubicon Express 4.5"
01 XJ Sport

There is a very fine line between "hobby" and "mental illness."
-- Dave Barry

Pronunciation: 'jEp
Function: noun
Date: 1940

Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase')
A small general-purpose motor vehicle with 80-inch wheelbase,
1/4-ton capacity, and four-wheel drive used by the U.S. army in
World War II.

(Please remove the OBVIOUS to reply by email)
__________________________________________________ _________

Re: High Oil Pressure Reading - Sending Unit?
 

Never would have thought of that.

Mike Romain wrote:

> I would be suspicious of a failed filter. If the filter fails
> internally, the oil pressure spikes and the bypass valve shunts it past
> the filter.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>

--
__________________________________________________ _________
tw

71 Bill Stroppe Baja Bronco
03 TJ Rubicon - Rubicon Express 4.5"
01 XJ Sport

There is a very fine line between "hobby" and "mental illness."
-- Dave Barry

Pronunciation: 'jEp
Function: noun
Date: 1940

Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase')
A small general-purpose motor vehicle with 80-inch wheelbase,
1/4-ton capacity, and four-wheel drive used by the U.S. army in
World War II.

(Please remove the OBVIOUS to reply by email)
__________________________________________________ _________

Re: High Oil Pressure Reading - Sending Unit?
 

Never would have thought of that.

Mike Romain wrote:

> I would be suspicious of a failed filter. If the filter fails
> internally, the oil pressure spikes and the bypass valve shunts it past
> the filter.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>

--
__________________________________________________ _________
tw

71 Bill Stroppe Baja Bronco
03 TJ Rubicon - Rubicon Express 4.5"
01 XJ Sport

There is a very fine line between "hobby" and "mental illness."
-- Dave Barry

Pronunciation: 'jEp
Function: noun
Date: 1940

Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase')
A small general-purpose motor vehicle with 80-inch wheelbase,
1/4-ton capacity, and four-wheel drive used by the U.S. army in
World War II.

(Please remove the OBVIOUS to reply by email)
__________________________________________________ _________