removing thermostat

[cmancini87]

So my oil pressure drops at an idle when warm. Tried replacing pump, main bearings, and rod bearings... still did it. So i decided to just remove the thermostat. Now it never gets warm so the oil pressure stays up. I know there is still a problem but at least it is fixed it for now. Just not sure if that can mess anything up? Any ideas? Would i be better off drilling a hole in the side of the Tstat? The temp guage never moves off 130 now.

 

[LB3711]

sounds like air in the system. Dont know if you can but bleed the air and make sure its full of fluid

 

[wingnut]

Bad idea on removing the t-stat. Since this is computer motor, it relies on input from the coolant sensor to set the operating parameters of the motor. If the computer (ECM) never sees the temp rising, then it will always assume a cold motor. Therefore you will always run rich, and gas mileage will be ****.
I chased this issue in my last truck, 95, 318, with a new oil pump and didn't solve the problem. Running 20-50 oil seemed to do it.
So I cant help you with the problem, but I can tell you that running no stat is not the answer.

 

[ParrotHead FA]

Running no t stat is great if you do a custom tune to set the computer to lean out the A/F ratio at 100 degrees. You wouldn't believe how it will extend the life of the engine, and also how clean it will stay, as the oil won't get hot enough to break down and leave behind all those varnish and sludge deposits in your engine with regular changes. You will also need to run hotter spark plugs, especially in an older engine, as with the engine running so much cooler, the stock plugs may not get hot enough to resist fouling. I've had a couple cars that were never run with a thermostat reach 400,000 miles or more before the engines needed an overhaul.
Dave

 

[vinper]

what about heavier wieght oil like 10/40?

 

[ParrotHead FA]

Heavier weight oil works good too. I personally would recommend 20w-50 for any engine that has over 100,000 miles, or for high performance engines used for racing or street/strip where they are subjected to high revs and hard use. Removing the thermostat and switching to a heavier oil like 20w-50 will solve most oil related issues such as oil burning, rear main seal leaks, low oil pressure, and compression loss. The combination of heavy oil and cool engine operating temperatures keeps the oil too thick to get by the rings, valves or oil seals in most cases. Obviously, this is not a substitute for proper mechanical repair, but if you want to keep that daily driver going without having to put a quart of oil in every week, it's a good remedy to get you by without spending a ton of money on oil. (at 3.50-4.00 a quart, it can add up quickly!) I have had a couple of old beater cars that were using around a quart of oil a week, after removing the t-stat and switching to 20w-50, they would only use about a quart or so every 3000 miles.
Dave

 

[BoredandStroked]

Have you replaced the actual oil-pressure sensor or used an engine oil pressure gauge tester? I personally would not have went into the rings and bearings and pump without testing those two things.

Short story on how tough these engines are. My engine has 230k on it right now with no knocks or bottom end problems. Last winter I had a full trailer load of furniture and other stuff to move into my new house, engine blew the head gasket 4 miles out of drive and started to overheat. I pulled over, checked oil level and found it was way over due to the coolant in it. Since it was 1 in the morning I told my girlfriend just to follow me because we are going to the house tonight. Drove 30 miles with the temp gauge at 260+ and a bunch of weird noises. Took the motor out and tore it down, checked head and block for warpage, no problems. Checked all bearings and end-play specs, no problems. Found a slight nick in one of the pistons, filed that down and honed the cylinder. Threw a gasket set on it and its been good sense, 20k miles after. Point of the story is these engines are hard to hurt in the bottom end.