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][\][iCk0411, Fleet Manager
Category: Medium and Heavy Trucks
Satisfied Customers: 67
Experience:  310T Red Seal- Truck and Coach Technician
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My cummings 330 in Peterbuilt. The warning light and alarm

Customer Question

My cummings 330 in Peterbuilt . The warning light and alarm come on at 200 deg. also fan will not kick in till after 203 deg. have to keep switch on and run fan all the time to keep temp. down
JA: We'll do all we can to help. Tell me a bit more about what's going on so the Heavy Equipment Mechanic can help you best.
Customer: also with fan on manual all the time temp will stay down but pull in to fuel up and shut down motor at restart overheat alarm will come on for 20 to 30sec
JA: Is there anything else important you think the Heavy Equipment Mechanic should know?
Customer: use to be might have temp run around 205deg without overheating ( alarm )with fan on auto would come on and off as needed
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Heavy Equipment Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  ][\][iCk0411 replied 1 year ago.

Hi, my name is ***** ***** welcome to Just Answer. I would be happy to try and help you today. I want to start with a couple questions regarding your defect and truck.

Do you have to turn the fan on manually all the time now? The fan will not work automatically anymore? Has only started doing the overheat condition since you have had to use the fan manually?

Once the fan is on manually it cools the motor just fine?

Thank you,

Customer: replied 1 year ago.
must keep on all the time or will go up to 200deg then alarm goes off then at 204deg fan comes on for 15sec
Used to go on auto at lower temp and stay on for 1to2 min.
auto comes on at much to high temp. manual will keep temp down but shut it off and auto does not kick in till temp is too high
Also when stopping for fuel ,fan on temp ok then turn off eng. at restart alarm and light comes on for 15sec then goes out even though temp is at 180deg
Expert:  ][\][iCk0411 replied 1 year ago.

My apologies for the delay Sir. So have you had any work done to it lately, or checked anything besides fluids yet? The more information, the better.

So to start I would recommend the following preliminary checks. First: Check your entire radiator to see if it may be getting plugged. Try to see if you can see light through the fins throughout the entire radiator. If it is hard to tell then try using a flashlight on the opposite side to try and see through. If you are having trouble seeing the light, or it looks dirty at all start by thoroughly washing the rad. The proper way to do this is to "Back Wash" So spray the water from the engine side back out the front. This makes sure that you don't plug the rad even more by forcing it back out the way it came.

Second I would check whether your coolant is building pressure while running. If you have a clear reservoir you should see the coolant moving while at idle. Your coolant pressure is regulated by your radiator cap so check the cap and if the system isn't reaching the pressure stated on the rad cap then I would recommend replacing your water pump. Sometimes its something small like the radiator cap is faulty. Please remember to not open the rad cap while the truck is running because it could be under pressure and spray hot coolant.

Please let me know your findings and we will proceed from there.


Customer: replied 1 year ago.
I will check the cap over the weekend Thanks
Expert:  ][\][iCk0411 replied 1 year ago.

Thank you!

Expert:  ][\][iCk0411 replied 1 year ago.

Hello Chris,

Have you had any chance to follow up on your truck? Let me know!

The question will stay open but could timeout within the next day unless you respond. I want to make sure your happy with your answer before that happens.


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