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TXST8tj 02-20-2008 09:31 AM

new head gasket and sending unit..still have oil pressure gauge issue
oil pressure gauge was dropping to zero after slowing down to a stop at a stop sign or intersection, etc. check gauges light came on at that time. replaced oil sending unit (twice). was also loosing coolant.

found out i had a leaking head gasket. replaced that and all that implies. drove it for the first time in 3 weeks (other than around the neighborhood last night) this morning to work. all was fine on the drive down the highway. when i exited and approached the intersection in front of work, the oil pressure gauge needle dropped to zero and the check gauges light came on. what else is there that i can do or check. it is getting pretty irritating, but i don't want to blow anything up...other than my jeep if it doesn't start cooperating soon.

after it cooled, i went outside to check the fluids (which had just been topped off last night). the oil looks good...color and level. the coolant level had dropped some. no drips or puddles that i could see. it was still on top of the core, but not in the fill neck like it was last night after filling. i topped it off and it took a decent amount to do so. we'll see if it lowers again. i would like to think it was just a matter of air bubbles working their way out, but i am not so optomistic.

is there something i am missing here. new hoses, new gaskets...thermostat, waterpump, cylinder head, machined head, resealed valves, new oil sending unit.

erickpl 02-20-2008 10:06 AM

I suspect that you had some air in the coolant system and they just had to bubble up. Coolant levels going down is pretty common after a flush fill.

Even here at this link they note that and you may have to top it off a couple of times until all bubbles are removed.

TXST8tj 02-20-2008 10:16 AM

thanks Paul. i am really hoping that is the case. i am ready to start enjoying this thing.

MOz 02-20-2008 10:59 AM

If you are still experiencing oil pressure problems, then I would suggest changing the oil pump and pick up screen. I'm sure the expresso latte is clumped up on your pick up screen following the leaky head gasket incident you posted a while back.

IMHO - purging the cooling system will not fix this problem.

How much did they get you to clean and prep the head?

TXST8tj 02-20-2008 12:02 PM

i think i will probably change the pump and screen. i would rather know that wasn't the problem.

after that if i have any issues, i'll just blow it up.

my98tj 02-20-2008 12:20 PM

have you replaced the oil pressure sensor?

TXST8tj 02-20-2008 01:12 PM

have not replaced the oil pressure sensor. just the oil sending unit...twice.

trav957 09-13-2008 11:01 AM

I'm having the exact problem with the oil pressure dropping to zero at a stop and when i idle out of a gear. I changed the oil and thought that did it but it happened again this morning. How would i find out where the oil pressure sensor is? also to change the screen and pump do you just have to take off the oil pan?

4.0l sahara 09-13-2008 11:12 AM


Originally Posted by TXST8tj (Post 196303)
have not replaced the oil pressure sensor. just the oil sending unit...twice.

same thing;)

rrich 09-13-2008 01:56 PM

I think you might be getting an oil problem mixed up with a cooling problem?

The "Check Gauges" light tells you to look at your gauges 'cause something isn't normal, nothing else.

When you saw the oil pressure was 0, what did the coolant temp gauge say?

If it was super hot that could be the reason for the low oil pressure.

If not, then it's a different problem.

After you changed the head gasket - before you started it, you did change the oil and filter -- I hope! If there was water and junk in the oil then and you did not dump it, it's still there.

Since the "check gauges" light came on, you can probably rule out a bad oil pressure gauge. A new sending unit would be logical.

You could also Tee in a mechanical oil pressure gauge at the sending unit to verify it's really losing oil pressure.

You need to know these things before you tear into it.

TXST8tj 09-18-2008 11:37 AM

haven't been on here in a while and i have actually since sold the TJ. it ended up that it had a cracked block.
the guy that bought it had the complete drivetrain out of an 05 TJ....4.0L, 5spd, driveshafts, etc.

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