Author Topic: Oil Pressure Drops To 20 psi Engine Quits  (Read 215 times)

Offline LJ-TJ

  • 14 year member
  • *
  • Posts: 2462
  • Member since: 2003
  • I own: a Motor Home
  • Year: 1975
  • Make: Winnebago
  • Model: D21
  • Chassis: Dodge
  • Engine: 440-3
Oil Pressure Drops To 20 psi Engine Quits
« on: February 07, 2019, 10:33 AM »
 Hm? Ok Boys got one for yeah!  So went out and started the 1975 440-3 today. After sitting for 4 months. She started right up oil pressure slowly but steadily worked it's way up to 70 psi. idleing at 700 rpm. Now I had problems with the old girl over heating this fall but what ever. Funny but it took quite a while for the water temp to come up but after about 20-30 minutes at idle it hit 150 deg. No oil temp. Not trans temp. Then there was what sounded like a change in idle speed and when I checked it, it had dropped to 500 rpm. AND the oil pressure started to drop steadily from 60 psi to 20 psi and the engine stopped on it's own. I waited a minute or two and then tried to start it again. It fired right up. Oil pressure went right to 62 psi with me stepping on the gas. As soon as I took my foot off the gas the idle dropped and the Oil pressure dropped steadily to 20 psi until the engine quit on it's own. Any thoughts? Oh! the oil temp and water temp never budged off 0 degs. Thanks Mates.

Offline BamBam

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  • Posts: 42
  • Member since: 2018
  • I own: I don't own one but I want one!
Re: Oil Pressure Drops To 20 psi Engine Quits
« Reply #1 on: February 07, 2019, 12:25 PM »
As a general rule, you should have at least 10 psi oil pressure for every 1000 rpms. I wouldn't worry about oil pressure.  As for the engine dying, I'd have to be there to see what's going on, could be lots of things? Dirty air filter, bad gas, clogged gas filter, low idle speed/carb adjustments, needs tune up, timing, etc. you get the idea?
Your cooling system, you say it overheated in the fall, it must be super cold outside now to only reach 150 after 20+ minutes, that's impossible. Do you have a thermos gun to get true temps from the motor as you should have overheated after 5-10 minutes with a cooling problem. It could be electricial, I don't know?
When's the last time this has had a good servicing like tune up items, cooling flush, belt's  hoses, etc.? Give more details what you've done, and what hasn't been done in a while. Good Luck

Offline Rickf1985

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  • Posts: 5185
  • Member since: 2013
  • I own: a Motor Home
  • Year: 1989
  • Make: Winnebago
  • Model: Chieftain
  • Chassis: Chevy
  • Engine: 454
Re: Oil Pressure Drops To 20 psi Engine Quits
« Reply #2 on: February 07, 2019, 02:24 PM »
What is the outside temp and humidity? And don't tell me you don't know mr. pilot. :D  If it is just around freezing and humid and your heat riser is not working my guess is the the carb is icing. Like was said the oil pressure is fine, too much oil pressure is bad. After 20-30 minutes you had 150 degrees water temp tells me that the thermostat is stuck open. Another thing to consider is if that has sat since fall with the same gas in it and it was not stabilized then the gas could be bad. It only takes an month for gas to start going bad, at least here in the states. Don't know if you have different formulations up there.


BamBam, You have never seen TJ's gauge setup have you? He can tell you the air temperature, and barometric pressure in Russia on that dashboard! W% :)rotflmao

Offline legomybago

  • *
  • Posts: 1160
  • Member since: 2013
  • I own: a Motor Home
  • Year: 1975
  • Make: FMC
  • Model: 2900R
  • Engine: 440
Re: Oil Pressure Drops To 20 psi Engine Quits
« Reply #3 on: February 07, 2019, 06:55 PM »
Sounds like you were running out of gas?
Never get crap happy with a slap happy pappy

Offline postman

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  • Posts: 132
  • Its all about prayers and shares
  • I own: a Motor Home
  • Year: 1977
  • Make: Itasca
  • Model: Suncruiser
  • Chassis: Dodge
  • Engine: 440-3
Re: Oil Pressure Drops To 20 psi Engine Quits
« Reply #4 on: February 07, 2019, 09:11 PM »
legomybago makes a good point fuel or fuel pressure.

Offline LJ-TJ

  • 14 year member
  • *
  • Posts: 2462
  • Member since: 2003
  • I own: a Motor Home
  • Year: 1975
  • Make: Winnebago
  • Model: D21
  • Chassis: Dodge
  • Engine: 440-3
Re: Oil Pressure Drops To 20 psi Engine Quits
« Reply #5 on: February 09, 2019, 05:21 PM »
Thanks Lads. We've been in a bit of a cold spell here and I haven't been able to get back out to look at the rig. BUT I'll check out all your suggestions and see what I can come up with. :)ThmbUp

 

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