Had different engine sound after oil change and replacing radiator, now resolved.

Zeus51 · Apr 14, 2020

Since the truck last ran well and normal, I have done the following:
replaced the radiator with Spectre b850
New Radiator hoses
Replaced oil dummy light sensor rear driver
Replaced glow plug sensor rear passenger
Replaced coolant sensor front driver
Replaced coolant crossover with HMMWV coolant crossover
Placed a paradox cooling system
Replaced glow plugs
Changed oil/filter 15w40

Currently, the truck will run but it now has this deep “womp” sound. Attached is a video of the noise. Also, the oil dummy light stays on. Prior to the leaking radiator, the truck ran great. Does anyone have any ideas? One member told me to check the water pump. Any other ideas?

edit: never mind. I can’t upload a video

cruzer747 · Apr 14, 2020

Zeus51 said:
Also, the oil dummy light stays on

Do not run it. Get mechanical gauge and hook it up. Disconnect fuel shutoff solonoid and crank. After some cranking I wold expect some oil pressure. If not something is wrong and you need to fix it. Do not run until oil pressure is verified mechanically.

Zeus51 · Apr 14, 2020

cruzer747 said:
Do not run it. Get mechanical gauge and hook it up. Disconnect fuel shutoff solonoid and crank. After some cranking I wold expect some oil pressure. If not something is wrong and you need to fix it. Do not run until oil pressure is verified mechanically.

I know I’m jumping steps. But what do you thinking would be wrong?

cruzer747 · Apr 14, 2020

shot that reply off as fast as I could, now that said... how long has it ran like this? After an oil change it is normal to take a few seconds longer for oil pressure to be restored after the first start but running without pressure is a very fast way to needing a new motor. Nothing that you changed should change any sounds but things I would check is make sure there is no air in the cooling system since you swapped radiator. Aside from that the only I cant really think of anything unless you dropped a rag in it that you used to plug a hole for debris while things were apart.... hopefully someone else will add but before oil pressure is verified do not run the thing.

cruzer747 · Apr 14, 2020

also check oil sensor housing to ground for continuity.

Zeus51 · Apr 14, 2020

cruzer747 said:
shot that reply off as fast as I could, now that said... how long has it ran like this? After an oil change it is normal to take a few seconds longer for oil pressure to be restored after the first start but running without pressure is a very fast way to needing a new motor. Nothing that you changed should change any sounds but things I would check is make sure there is no air in the cooling system since you swapped radiator. Aside from that the only I cant really think of anything unless you dropped a rag in it that you used to plug a hole for debris while things were apart.... hopefully someone else will add but before oil pressure is verified do not run the thing.

Hopefully I haven’t ran it too long. I’ve ran it for 4 periods of less than 3-4 mins. I do get a beep when testing the oil pressure sensor for continuity.

cruzer747 · Apr 14, 2020

Zeus51 said:
Hopefully I haven’t ran it too long. I’ve ran it for 4 periods of less than 3-4 mins. I do get a beep when testing the oil pressure sensor for continuity.

This is pointing towards needing the mechanical gauge to verify the no oil pressure condition before you figure out why. I would imagine the logical flow chart would be something like

Is there oil in it? >
Is the oil pump drive spinning it? (maybe your vacuum pump has come loose and hopped out of its home?) >
Is the oil pickup restricted? Maybe get a usb camera probe (~$10 on ebay) and drain oil and try and get access through drain plug?>
Is there something stuck at the filter mount or ?
Even with a clogged filter the bypass should open up (not that you would want that but it should not starve the engine...)

That is all I got, good luck and report in when you figure it out!

chevymike · Apr 14, 2020

Not sure if you have a Harbor Freight near you but they sell an oil pressure gauge tester. Pull the sender, screw in the adapter hose and connect to gauge. See what you are really getting. Try putting the old sender back in and see if the light goes out.

snowtrac nome · Apr 14, 2020

When you replaced the radiator did you remove the oil cooler, if the oil cooler and ports are plugged there is your problem. and yes now you will need a new motor

cruzer747 · Apr 14, 2020

snowtrac nome said:
When you replaced the radiator did you remove the oil cooler, if the oil cooler and ports are plugged there is your problem. and yes now you will need a new motor

Wouldn't a blocked off oil cooler just allow the bypass valve to open and still supply unfiltered pressure?

cucvrus · Apr 14, 2020

Relax. I have had a few motors take a long time to build oil pressure after sitting a long time. Not sure 3 minutes but I was worried on a few I bought not running and got running. What oil filter do you have on it? Water pump won't make the noise. You didn't drop anything down the intake? Do you have the vacuum lines hooked to the vacuum pump? That makes a strange noise. Good Luck. Report back.

cucvrus · Apr 14, 2020

They will run with the oil cooler line plugged and blocked off. I had to do it twice to plow trucks in the middle of the night. So I do think you are correct.

Zeus51 · Apr 14, 2020

Update... beer fixes everything. I’m not sure if me using a multimeter scrapper some of the crud off the wire for the oil pressure sensor or if time did it’s thing but:

I cracked a beer in disappointment and started staring at the truck. Then I put the lid to the overflow tank on and opened the radiator cap. Shoved a funnel in the radiator intake and cranked it one last time. The “womp” was loud and present for two revolutions (less than 5 secs) and then suddenly stopped as I was going around the truck to top off the coolant. Within 30 seconds it sounded like it did before I started draining oil and coolant. Nonetheless, I ordered an oil gauge yesterday so I probably won’t start it again and we’ll see what the pressure is when the gauge arrives. thank you guys for your quick help!!

M37M35 · Apr 14, 2020

cruzer747 said:
Do not run it. Get mechanical gauge and hook it up. Disconnect fuel shutoff solonoid and crank. After some cranking I wold expect some oil pressure. If not something is wrong and you need to fix it. Do not run until oil pressure is verified mechanically.

THIS!!!

After every oil change in anything, make sure it will build oil pressure!!
Years ago I did a simple oil change on a Chrysler industrial engine. On start-up, it would not build oil pressure for anything! I tried everything I could think of, even pumping oil into the oil passages from an external source. Apparently the oil pump was so worn it wouldn't prime. (even though it had good oil pressure before the oil change) I replaced the oil pump and the pressure picked right up and everything was good again.

So, I always make SURE the oil pressure picks up whenever I start an engine, especially after an oil change!

Curtisje · Apr 14, 2020

Zeus51 said:
Update... beer fixes everything. I’m not sure if me using a multimeter scrapper some of the crud off the wire for the oil pressure sensor or if time did it’s thing but:

I cracked a beer in disappointment and started staring at the truck. Then I put the lid to the overflow tank on and opened the radiator cap. Shoved a funnel in the radiator intake and cranked it one last time. The “womp” was loud and present for two revolutions (less than 5 secs) and then suddenly stopped as I was going around the truck to top off the coolant. Within 30 seconds it sounded like it did before I started draining oil and coolant. Nonetheless, I ordered an oil gauge yesterday so I probably won’t start it again and we’ll see what the pressure is when the gauge arrives. thank you guys for your quick help!!

I'm sure it's fine. I'll drink a beer here 'with' you.

Is the oil light off now?

Zeus51 · Apr 15, 2020

Curtisje said:
I'm sure it's fine. I'll drink a beer here 'with' you.

Is the oil light off now?

It is. The light went out as soon as it started the last time.

snowtrac nome · Apr 15, 2020

I would pull a sample and send it off it happened to me once on the same kind of engine it had spun a bearing than it spun back it worked for4 a week than the noise came back and stayed.

Zeus51 · Apr 15, 2020

snowtrac nome said:
I would pull a sample and send it off it happened to me once on the same kind of engine it had spun a bearing than it spun back it worked for4 a week than the noise came back and stayed.

You mean have it tested for copper and metallic flakes?

cucvrus · Apr 16, 2020

I think you are all good. I wouldn't worry about that. If you knew how many times I swamped a few M1009's in water and injected it thru the air filter you would be amazed the engine still ran and had good oil pressure. these 6.2 may not be fast and powerful. But I know for a fact they are durable. They take a beating and are hard to ruin in a few minutes of idle time. Not like you were slamming it on the rev limiter. And they do only go so fast. I think you will be fine. Enjoy your life and Take Care.

Had different engine sound after oil change and replacing radiator, now resolved.

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