Oil Pressure in 5 ton Gasser

[dfanders]

I have a 1953 M52 5 Ton semi with a Continental 6602 gas engine. She starts fine, and the oil pressure is good. After running her on the road for approx 20 minutes, the oil pressure begins to drop. over teh course of approx 10 minutes of driving, the pressure gauge drops to 10 PSI and i get a red indicator light. Truck shows no other signs of oil pressure issues( that i can tell) when this happens.
If you let it site for 30 minutes and cool down, when you re-start the oil pressure is back to normal.
I am new to this truck. This had happened with the previous owner , and he suspected a bad oil pressure sender?
If i go the route of replacing the sender , which is the correct part? Should I also replace the gge?

I was thinking of taking it to a mechanic who works on 5 tons. I am concerned that when teh oil gets warm , it is leaking past seals & valves. If you know the gasser engine, you know that i can't just look back ato tell if i am blowing the correct color smokle from burinng oil...the gasser engine burns so much gas that it is always blowing cloud of white smoke behind it !!

Thanks,
David


Thoughts?

 

[gimpyrobb]

Try a mechanical gauge.

http://www.steelsoldiers.com/showthread.php?t=25112&highlight=oil+pressure

 

[m139h2otruck]

When we first started our truck, the gauge was NG, so I installed a cheap VIP import direct gauge w/ nylon tube and hung it from the wiper. It would run @ about 60+ psi, until good and warmed up and then drop to 25-30 or so at idle and 60 more or less at speed. The electric sender/gauge on these trucks can not always be trusted.

 

[m139h2otruck]

Also, your comment about white smoke from the exhaust, ours, when fully warmed up has no real smoke going down the road, just a lot of heat clouds and a small amount of black smoke when under a load or when the gas pedal is mashed. Looks a little like it has a turbine for an engine. White smoke all the time may be a problem with water in the cylinders.

 

[rmgill]

Dave, get an engine oil analysis kit from NAPA. I've got a pair of them on order for Norm's M818 and my M35. We'll keep a running set of values on these and probably ought to do the same for the armor. The nice thing about an analysis it will tell you if you have bearing issues or other metallurgical issues with the engine as well as tell you if the truck has problems.

A mechanical gauge to check the accuracy of the main gauge can be added to the block to check the pressure but not used long term.

BUT, check the ground on the electrical gauge to be sure its good. Take the gauge's back plate off, scuff the contact points where the U-bracket touches the instrument panel and add some dielectric grease, then re-assemble. Replacing the gauge might be needed too.

Guys, this is the M52 that was bought from VMMV by Armyman30 Years. He sold it to Dave up there.

 

[rmgill]

Also, your comment about white smoke from the exhaust, ours, when fully warmed up has no real smoke going down the road, just a lot of heat clouds and a small amount of black smoke when under a load or when the gas pedal is mashed. Looks a little like it has a turbine for an engine. White smoke all the time may be a problem with water in the cylinders.

You think maybe the head gasket is coming open as it comes up to temperature and that's allowing a loss of oil pressure?

 

[dfanders]

Ryan,

How do i check the head gasket? When I say smeoke, it is more that fact that you have a lot of fuel fumes from the rear end. I have been told , this , to some extent is normal for a gasser engine.

Maybe it is a good idea to just get that changed...

 

[BEASTMASTER]

my truck runs 50lds when just started and running normal . when hot and idling it is just over 10lds. been like that for 5 years now.

 

[dfanders]

Beastmaster,

Thanks for your input ! It seems this may be normal for the truck. I will go thru the sender and gge, clean it up and see if that changes anything. after that , i will look at changeing out the gge and sender. I will also do an oil check, to see if i am geeting water in the engine.

Cheers,
David

 

[BEASTMASTER]

yep i think so . i teed in a mechanical gauge for safe t and it read the same as the original gauge . so i just live with it ,. my buddie says there is a releif valve in there some where so you dont blow out the orings in the winter when the oil is real thick.