John Deere 3520 Air restriction light check

[bubbacuse77]

So I go to do the 400 hour service on my 3520 and the owners manual calls for a person to block the air intake and run the throttle all the way up to check the air restriction sensor. When you do this it should set off the air restriction indicator light on the dash to check to make sure the sensor is working properly. So I did this and it never came on, I even used duct tape to make sure it was blocked well. The funny thing is that the engine didn't even labor with the air intake blocked off. I checked for good air movement through the intake when the blockage was off and it was moving allot of air past my hand. I can't find any air leaks else where so I am assuming the sensor is bad but it really puzzles me that the engine didn't seem to run any different at wide open throttle with the air intake blocked?

Any body else with a 30-20 series experience this?

 

[bubbacuse77]

Anybody? I'll send this up one more time.

 

[dschuffert]

I did the test when I first got my 3520 and had the same result. I pulled the air cleaner box off the tractor and found the plastic cracked where it goes into the area around the radiator in front of the air restriction sensor. The dealer replaced the air box under warranty and the subsequent test worked as described in the manual. I also performed the test when I got my 3720 back in July. The 3720 worked the first time.

 

[shortthrow50]

Hey man, I'll give this a try tomorrow and let you know the outcome

 

[puckgrinder85]

If you blocked it off well enough the engine tone should have changed, you must not be blocking off enough air or like the other guy said its coming in somewhere else. I wouldnt put anything over the intake that could get pulled in, duct tape is a really bad idea. If you have a turbo, kiss it goodbye.

 

[bubbacuse77]

If you blocked it off well enough the engine tone should have changed, you must not be blocking off enough air or like the other guy said its coming in somewhere else. I wouldnt put anything over the intake that could get pulled in, duct tape is a really bad idea. If you have a turbo, kiss it goodbye.

The JD owners manual has you block the intake pre filter so it would only go against air filter if it gets sucked in.

 

[bubbacuse77]

Hey man, I'll give this a try tomorrow and let you know the outcome

Thanks short I'm anxiously awaiting your results

 

[bubbacuse77]

I did the test when I first got my 3520 and had the same result. I pulled the air cleaner box off the tractor and found the plastic cracked where it goes into the area around the radiator in front of the air restriction sensor. The dealer replaced the air box under warranty and the subsequent test worked as described in the manual. I also performed the test when I got my 3720 back in July. The 3720 worked the first time.

There is a natural gap where the air filter housing fits into the radiator housing but I'm not able to picture where exactly you are describing.

 

[shortthrow50]

Thanks short I'm anxiously awaiting your results

had such a crazy day and totally forgot. I promise results tomorrow night

 

[bubbacuse77]

Some days are that way