5740 starting oil pressure delay.

   / 5740 starting oil pressure delay. #1  


New member
Jul 20, 2020
Montana 5740
I have a 2005 Montana 5740 with the Mitsubishi S4S engine and it had 800 hours on it.
It seems to take an extremely long time to build oil pressure when first started in the morning. Even with a 70 degree outside temperature it takes almost 6 full seconds with the engine at idle to turn off the oil pressure light.

If any of you 5740 or 5720 owners could check how long it takes for the oil pressure light to go off when your tractor is started first time of the day I would appreciate it if you would let me know if this is normal.
   / 5740 starting oil pressure delay. #2  
Just because the light is on does not mean you don't have pressure. Newer gauges have tiny holes like size of a hair. Which is good because if it fails, it won't blow oil out fast and ruin your engine. But, cold thick oil takes a little bit to open gauge.
   / 5740 starting oil pressure delay.
  • Thread Starter
I've never looked to see if it's a mechanical or electrical gauge.
Unfortunately when the oil pressure light goes out I also hear the engine quiet down when the oil hits the moving parts. I'm not looked but I assume that s4s does not have hydraulic lifters so I assume it quiets down from the oil hitting the camshaft, pistons or the crank bearings.
I appreciate your input and hadn't thought about that so I will put a mechanical gauge on to check it.
   / 5740 starting oil pressure delay. #4  
There can be a few things that will cause that,
one is a filter without a drain back valve.
Or wear on the engine or oil pump.
Many times it's the oil weight or type.
Synthetics will often pump faster then other oils.
   / 5740 starting oil pressure delay.
  • Thread Starter
My concern is oil pump wear, leaky o-ring or a leak in the pressure line after the pump. As you probably know most engine wear occurs during startup.
10w-30 non-synthetic oil.
I also had checked the filter specs and it does have an anti-drain back valve, or supposed to have one if it isn't stuck.
Thanks for responding, it's good to have someone to bounce ideas off of.