what are you guys using for fluid in the isolator line from the isolator line to the gauge?im just hung up on what to use and waiting to install....also is it necessary to bleed the line from the isolator to the gauge or is pressure simply pressure?

 

Isolator? Most of us run fuel straight to the gauge, with a shutoff valve under the hood in case something happens upstream.

Isolators use plain old 50/50 water/green anti-freeze and the line needs to be absolutely full for an accurate reading.

 

Does the isolator serve to reduce gauge flutter as well ? I'm torn between using one or not, I've seen some needles shake so bad it would drive me nuts just to have to look at it..

 

I have heard more bad, than good, about gauge isolaters.


Like Dave already said, all of mine are plumbed exactly in the same fashion as a mechanical oil-pressure gauge, with the addition of a gauge-snubber that arrests the erratic fluctuations that bounce the needle.


I use 1/8-NPT ball-valves and snubbers from McMaster-CARR, that have male-threads on one end and female-threads on the other end.

Look here for the part number for the snubber :

https://www.dieseltruckresource.com/...16&postcount=6


I start at either a TEE-fitting, or a BIG-BANJO-BOLT, with first a 1/8-NPT ball-valve, then a gauge-snubber, then the line that plumbs into the gauge itself.

In all the years that I have had fluid-pressure lines ran into the cabs of trucks, I have never had one leak; careful assembly and attention to detail is the key to a successful installation.

The ball-valves are an emergency back-up plan that will shut off the flow of oil or fuel, should a leak occur.


This funny story is appropriate for this discussion :

My father has this bone-head employee that is a constant source of entertainment. He has this old loud noisy souped-up on a budget/credit Cutlass Olds. He jumped in it, one day, and hit the starter, immediately revving the engine to the floor. About the third punch of the pedal, the oil-pressure line parted company with the gauge, immediately filling his shoe with hot oil, and soaking the carpet.

It is un-believable how much oil squirted through that tiny tube, in the few seconds it took him to shut off the engine.

 

Anyone wanna buy an isolator?

 

I had a similar thing happen to me in my old D250 gasser. The PO had "installed" an oil pressure gauge. It had no light wired up, but the oil pressure was always good and I didn't care too much about the rusty old pile anyhow. On the way to work at 5:30 one cold dark morning I started smelling oil in the cab. Went to pull over to investigate and noticed that the floorboards were very slippery. That clued me in on the cause of the problem pretty quick. I went under the hood and yanked the tube out of the firewall, pulled out the breather, put the end of the tube in the valve cover and stuffed the breather back in. Then I dumped in a quart of oil and continued on to work. That evening's project was putting a pipe plug in the pressure port and cleaning the oil out of the cab.