Injector/nozzle question

[jbach36]

My car is now idling too loud. It has 240k on it. The injectors were cleaned maybe 3 years ago but never pop tested or anything. Rather than re-cleaning them, etc., is it time to get new injectors or do you keep the injectors and just get new nozzles?

I'm figuring there's no reason to clean and pop test these original injectors because if they currently work fine today, they might not tomorrow since they're the originals.

My car is not smoking or idling rough. Just louder than it should be.

1991 300d

[nastala]

The injectors are technically nozzles and nozzle holders. You just replace the nozzles, then they are pop tested and re-shimmed as appropriate. No reason to not pop test, you can get the thing on ebay or something for sub $100. Louder than it should be in what way? If it's a mild nailing noise, it could be due to low pop pressure advancing timing.

[jbach36]

I've heard good things about Monarch nozzles. I'll try to find out which are the right ones for my car and take a look.

I could do a complete Molly Lube clean on my injectors, that would help for now.

[Diesel911]

Originally Posted by jbach36

I've heard good things about Monarch nozzles. I'll try to find out which are the right ones for my car and take a look.

I could do a complete Molly Lube clean on my injectors, that would help for now.

There is a thread somewhere saying Monark is no longer making Nozzles. There may or may not be old stock left on some sellers shelves.

I have 2 diesels using the Monarks for may years and am entirely satisfied with them.

Need of a Valve Adjustment on engines where that is adjusted can cause the noise (from combustion called nailing) as can Fuel Injection Pump timing to retarded/late or too advanced. Low compression can cause nailing.

[BillGrissom]

Idle noise can also vary with the fuel, so first try other stations. My 1984 300D idles so quietly on renewable diesel that you can barely tell it is a diesel engine. But, you can only buy it at the pump in California (carbon credits), either Propel HPR or Union 76 R99. Some people add a quart of vegetable oil each fill-up to help clean the innards and perhaps smooth the idle. I never tried. You might be able to buy B20 fuel in the southeast, especially at truck stops on the interstate.