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Wed Mar 05, 2025 8:14 pm

Rebuilding my tdi 1z, originally out of a 1996 Passat. I’ve removed the oil squirters and blown air through them. They all flow fine with no clogging but the spring loaded pressure check balls seem to have very light spring pressure. So light that they lift the ball from its seat and begin to flow almost right of the bat. (1-2psi) and by idle pressures of say 15 psi will be flowing strong for sure. Is this normal? Or do they wear out. I have the early kind squirter’s with a separate solid screw which fastens them to the block. Not the kind with a hollow single screw. Thanks, Paolo.

Thu Mar 06, 2025 9:25 am

I don’t know the exact answer, but the springs probably have something to do with drain back, not opening pressure. The engines had a higher volume oil pump and the nozzles are the restriction and it’s likely you aren’t loosing any oil pressure having them spraying all the time. This will bump your post.

Thu Mar 06, 2025 11:34 am

MarkWard wrote: I don’t know the exact answer, but the springs probably have something to do with drain back, not opening pressure.

they are actually sold as 'check valves'!!!

https://techtonicstuning.com/product/20l-piston-squirter-check-valve/

Thu Mar 06, 2025 12:40 pm

you're fine

they are just barely pissing oil at that pressure. The fun begins at 2k/40 psi

Thu Mar 06, 2025 1:22 pm

They aren't supposed to leak at idle. The reason for the valve in them is to prevent them from lowering idle oil pressure. They would just be an open port otherwise. It might not be a big deal, though, depending on what your idle oil pressure actually is. I've tested them before with an injector pop tester with a swapped in lower pressure gauge. I believe the Mk2 Bentley gives the pop pressure, I don't recall if the Mk3 does. It was years ago, so the details are foggy.

Thu Mar 06, 2025 8:15 pm

Hello, thanks for the replies. The early check valves which were used in early 1z Tdi’s is what I have , they are different than the later check valves in that they do not have a restriction other than the size of the nozzle itself. Both have the spring/ball check valve , but The later check valves have a small hole drilled into the center bolt which further restricts flow and must delay the opening of the spring/ ball check valve.
Does anyone know why they made this change? Is it possible to retrofit the newer style check valves in my block if indeed, they don’t open until a higher pressure , thus helping out with hot idle lubrication. Thanks, Paolo.