oil pressure gauge almost pegged at 80 - Tilted Forum Project Discussion Community

JStrider · 01-03-2005, 06:51 PM

ok my dad has a 2000 jeep grand cherokee
its got the 6cylinder engine
2 wheel drive

it was about 1000 miles overdue for its 3000 mile oil change... and we were vacationing in mammoth (very very cold/snowy/icy) we started the car and then left it idling for about 20 minutes while we cleared away the snow... when we got in the needle was all the way to the max end of the oil pressure gauge, by the 80

whenever we start the car the needle zooms up to the 80 right away

i gave it the overdue oil change... but it doesnt seem to have helped at all...

anyone have any ideas...

the car is here so if you have things i can check just lemme know...

cyrnel · 01-03-2005, 07:02 PM

How many miles on the engine?
Is it still cold where you are?
What oil viscosity are you using? Any additives?
The oil pressure sender might be faulty. Buy a dash gauge and "t" it in at the sender (by the oil filter) to test. A cheap one is fine - it's just for a reality check.

A 4000 mile oil change interval is insignificant for modern engine oils unless the daily drive consists of 1 mile trips or the engine is in terrible condition.

Psycho Dad · 01-03-2005, 07:04 PM

Likely the sending unit. But it could be clogged cam bearings or such. I'd get it checked.

JStrider · 01-03-2005, 07:15 PM

How many miles on the engine?
70968 (my dads pretty grumpy about it... had warranty to 70 000)

Is it still cold where you are?
not as cold as where we were visiting... daytime low 60s upper 50s
What oil viscosity are you using? Any additives?
using 5w30 oil ... its castrol syntec blend no additives added

A 4000 mile oil change interval is insignificant for modern engine oils unless the daily drive consists of 1 mile trips or the engine is in terrible condition.
well... my sister has been driving to school,her babysitting job, and home... probably a few half mile trips a day...

cyrnel · 01-03-2005, 07:19 PM

If you have a multimeter:

1 Ohm = 0psi
46.5 Ohms = 40psi
87 Ohms = 80psi

Those are earlier 4.0L HO values but I believe they're correct through 2004.

JStrider · 01-03-2005, 07:36 PM

my dad has a multimeter... we'll have to dig it out of the garage...

oh... didnt mention this earlier... but the car is running fine... doesnt seem to be any problems other then on the gauge...

cyrnel · 01-03-2005, 07:38 PM

5w-30 Syntec should pump acceptably down to ~-25C.

Check the sender or just replace it. It's ~$25 depending on your dealer. You might catch me whining about the recent warranty expiration to improve price.

The Syntec we get in the USA is a group III (semi-synth) but unless you've really abused the change intervals (10K multiple times) you're doing fine. 4K miles is just getting warmed up.

You're maybe at 1/4 of the engine's life. Those I6's can last a very long time.

JStrider · 01-03-2005, 07:48 PM

how would we check the sender?

i know its supposed to be located by the oil filter...

cyrnel · 01-03-2005, 09:10 PM

Sorry, googled in vain for a picture of yours. The sender should be at the top of the oil filter, just a bit closer to the block. They get knocked off quite a bit by oil change shops.

I believe your 2000 is still a two-wire. Pull off the locking clip and check sender resistance engine off and at idle. It can be easy or not depending on the type of clip.

cyrnel · 01-03-2005, 09:11 PM

Oh, if the clip is loose or oil drools out when you remove it then you found the problem.

JStrider · 01-03-2005, 10:34 PM

ok theres 3 things by the fuel filter that look like they could be it...

the oil filter is the green arrow

the blue arrow thing looks like 2 wires smushed beneath a metal plate going to the side of the engine

the yellow arrow is a little black box thing bolted to the side of the engine with 2 wires coming out... we couldnt get the clip off to mess with it at all...

the red arrow is a cylindrical thing coming out of the engine... we pulled the connector off it and there were 3 wires connecting to it inside the connector... and the car would not start with the cap off..

know which of those is the sender?

cyrnel · 01-04-2005, 12:17 AM

It should be right at the top of the filter, covered in grease no doubt. I can't see it in your picture but it's pretty dark in that area. Look between the yellow arrow and the filter for a small black cylinder. One end threads into the oil filter mount and the other has wires coming from it.

It's possible they moved it below to reduce breakage during filter changes, or it may have just rotated with the oil filter mount/adapter. There are about 8 versions of those mounts pointing in different directions depending on the vehicle.

MSD · 01-04-2005, 10:28 AM

Some Cherokees have a one-wire sensor with the engine block used as the ground. It should be right above the filter. Two-wire sensors are used on the V8, but most I6's are single-wire. Look for a white wire coming out of a cylidrical housing on the oil filter mount. It may be off to the side or on the bottom, I forget what year they switched it. Since the filter has to be changed from the top, it's too easy to rip the wire out with a filter wrench or a careless finger.

If you can't find it, I'll check on the next Jeep I work on. I'm pretty sure that Jeeps are close to 20% of our business.

JStrider · 01-04-2005, 02:38 PM

I didnt have any trouble changing the filter from below... its pretty easily reachable from above and below...

my dad and i arnt really seeing anything thats meeting your descriptions...

my dads gonna take it into the shop thursday if we dont get it figured out before then..

MSD · 01-16-2005, 11:34 PM

It's a bit late now, but the unit should be located approximately 8-10 inches directly back from the oil filter with a single wire coming out of it.

cyrnel · 01-17-2005, 12:06 AM

msd, is that true of all 4.0L WJ's?

I did see the sensor for the 2k though and it was a 2-wire harness like earlier models. Of course, the parts counter guy may have forkled up the database query...

01-03-2005, 06:51 PM	#1 (permalink)
JStrider Poo-tee-weet? Location: The Woodlands, TX	oil pressure gauge almost pegged at 80 ok my dad has a 2000 jeep grand cherokee its got the 6cylinder engine 2 wheel drive it was about 1000 miles overdue for its 3000 mile oil change... and we were vacationing in mammoth (very very cold/snowy/icy) we started the car and then left it idling for about 20 minutes while we cleared away the snow... when we got in the needle was all the way to the max end of the oil pressure gauge, by the 80 whenever we start the car the needle zooms up to the 80 right away i gave it the overdue oil change... but it doesnt seem to have helped at all... anyone have any ideas... the car is here so if you have things i can check just lemme know... __________________ -=JStrider=- ~Clatto Verata Nicto

01-03-2005, 07:04 PM	#3 (permalink)
Psycho Dad Mulletproof Location: Some nucking fut house.	Likely the sending unit. But it could be clogged cam bearings or such. I'd get it checked. __________________ Don't always trust the opinions of experts.

01-03-2005, 07:15 PM	#4 (permalink)
JStrider Poo-tee-weet? Location: The Woodlands, TX	How many miles on the engine? 70968 (my dads pretty grumpy about it... had warranty to 70 000) Is it still cold where you are? not as cold as where we were visiting... daytime low 60s upper 50s What oil viscosity are you using? Any additives? using 5w30 oil ... its castrol syntec blend no additives added A 4000 mile oil change interval is insignificant for modern engine oils unless the daily drive consists of 1 mile trips or the engine is in terrible condition. well... my sister has been driving to school,her babysitting job, and home... probably a few half mile trips a day... __________________ -=JStrider=- ~Clatto Verata Nicto

01-03-2005, 07:36 PM	#6 (permalink)
JStrider Poo-tee-weet? Location: The Woodlands, TX	my dad has a multimeter... we'll have to dig it out of the garage... oh... didnt mention this earlier... but the car is running fine... doesnt seem to be any problems other then on the gauge... __________________ -=JStrider=- ~Clatto Verata Nicto

01-03-2005, 07:38 PM	#7 (permalink)
cyrnel Adequate Location: In my angry-dome.	5w-30 Syntec should pump acceptably down to ~-25C. Check the sender or just replace it. It's ~$25 depending on your dealer. You might catch me whining about the recent warranty expiration to improve price. The Syntec we get in the USA is a group III (semi-synth) but unless you've really abused the change intervals (10K multiple times) you're doing fine. 4K miles is just getting warmed up. You're maybe at 1/4 of the engine's life. Those I6's can last a very long time. Last edited by cyrnel; 01-03-2005 at 07:40 PM..

01-03-2005, 07:02 PM	#2 (permalink)
cyrnel Adequate Location: In my angry-dome.	How many miles on the engine? Is it still cold where you are? What oil viscosity are you using? Any additives? The oil pressure sender might be faulty. Buy a dash gauge and "t" it in at the sender (by the oil filter) to test. A cheap one is fine - it's just for a reality check. A 4000 mile oil change interval is insignificant for modern engine oils unless the daily drive consists of 1 mile trips or the engine is in terrible condition.

01-03-2005, 07:19 PM	#5 (permalink)
cyrnel Adequate Location: In my angry-dome.	If you have a multimeter: 1 Ohm = 0psi 46.5 Ohms = 40psi 87 Ohms = 80psi Those are earlier 4.0L HO values but I believe they're correct through 2004.

01-03-2005, 07:48 PM	#8 (permalink)
JStrider Poo-tee-weet? Location: The Woodlands, TX	how would we check the sender? i know its supposed to be located by the oil filter... __________________ -=JStrider=- ~Clatto Verata Nicto

01-03-2005, 09:10 PM	#9 (permalink)
cyrnel Adequate Location: In my angry-dome.	Sorry, googled in vain for a picture of yours. The sender should be at the top of the oil filter, just a bit closer to the block. They get knocked off quite a bit by oil change shops. I believe your 2000 is still a two-wire. Pull off the locking clip and check sender resistance engine off and at idle. It can be easy or not depending on the type of clip.

01-03-2005, 09:11 PM	#10 (permalink)
cyrnel Adequate Location: In my angry-dome.	Oh, if the clip is loose or oil drools out when you remove it then you found the problem.

01-03-2005, 10:34 PM	#11 (permalink)
JStrider Poo-tee-weet? Location: The Woodlands, TX	ok theres 3 things by the fuel filter that look like they could be it... the oil filter is the green arrow the blue arrow thing looks like 2 wires smushed beneath a metal plate going to the side of the engine the yellow arrow is a little black box thing bolted to the side of the engine with 2 wires coming out... we couldnt get the clip off to mess with it at all... the red arrow is a cylindrical thing coming out of the engine... we pulled the connector off it and there were 3 wires connecting to it inside the connector... and the car would not start with the cap off.. know which of those is the sender? __________________ -=JStrider=- ~Clatto Verata Nicto

01-04-2005, 12:17 AM	#12 (permalink)
cyrnel Adequate Location: In my angry-dome.	It should be right at the top of the filter, covered in grease no doubt. I can't see it in your picture but it's pretty dark in that area. Look between the yellow arrow and the filter for a small black cylinder. One end threads into the oil filter mount and the other has wires coming from it. It's possible they moved it below to reduce breakage during filter changes, or it may have just rotated with the oil filter mount/adapter. There are about 8 versions of those mounts pointing in different directions depending on the vehicle.

01-04-2005, 10:28 AM	#13 (permalink)
MSD The sky calls to us ... Super Moderator Location: CT	Some Cherokees have a one-wire sensor with the engine block used as the ground. It should be right above the filter. Two-wire sensors are used on the V8, but most I6's are single-wire. Look for a white wire coming out of a cylidrical housing on the oil filter mount. It may be off to the side or on the bottom, I forget what year they switched it. Since the filter has to be changed from the top, it's too easy to rip the wire out with a filter wrench or a careless finger. If you can't find it, I'll check on the next Jeep I work on. I'm pretty sure that Jeeps are close to 20% of our business. Last edited by MSD; 01-04-2005 at 10:32 AM..

01-04-2005, 02:38 PM	#14 (permalink)
JStrider Poo-tee-weet? Location: The Woodlands, TX	I didnt have any trouble changing the filter from below... its pretty easily reachable from above and below... my dad and i arnt really seeing anything thats meeting your descriptions... my dads gonna take it into the shop thursday if we dont get it figured out before then.. __________________ -=JStrider=- ~Clatto Verata Nicto

01-16-2005, 11:34 PM	#15 (permalink)
MSD The sky calls to us ... Super Moderator Location: CT	It's a bit late now, but the unit should be located approximately 8-10 inches directly back from the oil filter with a single wire coming out of it.

01-17-2005, 12:06 AM	#16 (permalink)
cyrnel Adequate Location: In my angry-dome.	*msd*, is that true of all 4.0L WJ's? I did see the sensor for the 2k though and it was a 2-wire harness like earlier models. Of course, the parts counter guy may have forkled up the database query...