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russfortin
06-26-2007, 07:01 PM
I'm posting like crazy now, love this site!

I have one other problem in my 87 prostar. When i initially start the engine i get an oil pressure around 60 or so and over the next five minutes it eventually goes down to about zero and stays there. Everytime i shut the engine down and restart throughout the day, it'll be back up at 60 or so for a few more minutes. Theres no engine knocking or anything to make me believe that the guage is correct and there is no oil pressure. And, it might not be good, but i've run it almost everyday for a year now with this problem.

any pointers on what to check, maybe something in clogged??
Thanks

Russ

M-Funf
06-26-2007, 07:13 PM
Since the gauge is probably an electric, you could check the sender...heck, might as well just replace it and see if that works. If you put a new sender on and you still get Zero, then you should hope that it's a bad gauge...

russfortin
06-26-2007, 07:34 PM
where is the sender located? what does it look like? should be no problem to replace it, just not sure where, thanks

M-Funf
06-26-2007, 07:57 PM
Attached to this thing somewhere...


http://www.tmcowners.com/photopost/data/500/medium/129_2984.JPG


Sorry...Sorry...I couldn't resist :rolleyes:

I'm not exactly sure. It may look something like this with one wire attached to the top...
http://www.skidim.com/images/R020001.jpg

Skidim has them for 30 bux...

http://www.skidim.com/prodinfo.asp?number=R020001

85S&S_Keuka
06-27-2007, 09:23 AM
I'm not exactly sure. It may look something like this with one wire attached to the top...
http://www.skidim.com/images/R020001.jpg



Yep, that's what it looks like. It's on the port side of the engine (assume you have a 351), above the oil filter. Mine was good enough to show somthing on the gauge if the pressure was above 50psi, but once it warmed up enough to drop below that, it would read 0.

P-hat_in_Cincy
06-27-2007, 09:56 AM
Agreed with the picture above. Just fyi...Since mine is original, it's painted black along with the rest of the engine/components.

cwright
06-27-2007, 11:08 AM
I had bouncing oil pressure last year causing my low oil alarm to chirp when it bounced below 10. I replaced the sending unit and problem went away. Be forewarned however, the 1/4" nipplle that screws into the block will probably break off. Mine did and I've read others post that theirs did too. Don't do this without a hardware store nearby to resupply the 1/4" fittings that get mangled in the process. Good luck.

MIMC
06-27-2007, 06:07 PM
I agree with all the posts so far, replace the sending unit. If the problem still exists I'd recommend attaching a "wet" oil gauge to check psi. The gauge will screw in right where the sending unit would be. A good gauge won't lie. Also, psi will be higher when the engine is cold - once at operating temp psi will drop.

M-Funf
06-27-2007, 06:15 PM
I'd recommend attaching a "wet" oil gauge to check psi. The gauge will screw in right where the sending unit would be.

Another idea would be to install a "tee" at the block so you could attach the sender and a remote "wet" pressure gauge. That way, you can compare the dash gauge with the "wet" gauge.

bowtie355
06-28-2007, 01:50 PM
Yep, that's what it looks like. It's on the port side of the engine (assume you have a 351), above the oil filter. Mine was good enough to show somthing on the gauge if the pressure was above 50psi, but once it warmed up enough to drop below that, it would read 0.
My 85 SS did the same, I replaced the transducer and the gauge works normal.
Dan

russfortin
06-28-2007, 01:59 PM
ok, so i was taking the old one off and, as expected, the tubing broke. I found an oil pressure switch at autozone that looked basically identical, and half the price. I got some brass tubing and installed the new pieces. only thing now is when i put the wire back on the guage immediatly spikes. is that just because i havent run the engine yet to get the sender "warmed up" or did i mess the whole thing up. thanks for the help guys


its pouring rain here in texas for like the next month, so the boats in my garage...thats why i havent started the engine!

bowtie355
06-29-2007, 12:31 AM
ok, so i was taking the old one off and, as expected, the tubing broke. I found an oil pressure switch at autozone that looked basically identical, and half the price. I got some brass tubing and installed the new pieces. only thing now is when i put the wire back on the guage immediatly spikes. is that just because i havent run the engine yet to get the sender "warmed up" or did i mess the whole thing up. thanks for the help guys its pouring rain here in texas for like the next month, so the boats in my garage...thats why i havent started the engine!

I changed my oil pressure gauge transducer a week ago with a Teleflex Morse at Boaters World. It worked perfect. Make sure the transducer goes from 0-80 PSI and is 240-33 OHMS,Otherwise the calibration to your gauge might be off. One bonus going with Teleflex Morse, it was made in the USA!!! http://images.corvetteforum.com/images/smilies/patriot.gif