Crack at Oil Pressure Switch Port

Hello,

I was trying to track down a small leak coming from the Oil Pressure Switch and replaced it with a new one, it is likely I overtightened the new sensor. When I started the vehicle, oil was pouring out of a crack in the block where the switch mounts. What are my options? End of the road for this engine? Thanks in advance.

 

Yes unfortunately this is non-repairable

any "patch job" can fail and will release all oil pressure abruptly.

If it were mine I'd try to plug it with jb weld just for moving it around the yard until I can find a block.

 

You could drain the oil. Spray the area with brake cleaner. Fill it with a good amount of JB Weld and call it a day with no more sensor. This will work.

 

You should be able to install a thread repair heli coil. Check around and see if someone will do it.

 

the problem is any attempt to "fix" this leak by tightening the sensor will only expand the crack and make it worse due to the taper of the pipe thread. I have pinned a few cast iron blocks in my days... older Interntional 6.9's... and have had excellant results. I drove my truck close to 200,000 miles after the repair with zero issues using this method when the "experts" said it was junk.

The big problem you will have is access to the crack, at least while the motor is still in the truck. Carefully drilling into the oil galley and measuring the depth for pin intallation so that you dont partially block oil flow is another concern. If you have the time and the ability to try it I figure what do you have to lose?

3.4's are pretty common still so if your going to pull the motor to fix it you might as well replace it and have the piece of mind. If you have to pay someone to do the work thats a problem.

https://www.youtube.com/watch?v=Pq0wfU4ZaKk

 

In any case without seeing this .

Did the block crack or the sensor ?

How many miles since the engine would need to come out getting a lower mileage 3.4 might be the way to go

The problem with castings is the thermal cycling

 

Thanks for the replies. After some further research I’m leaning towards JB plug with maybe a hose clamp while I source a new engine. Here’s a picture of the damage. Engine has 211k on it. A very expensive mistake.

 

That is some badass stuff, learned something new today

 

well... crap. That crack isnt fixable. I would clean it off and take the sending unit out and JB weld it and like you said, put a hose clamp on it and screw the sensor back in 2 turns and start her up after the JB sets and see if she leaks, if she does maybe another 1/2 turn... so afraid that the casting is just to break off completely and she is stuck where she broke.

 

Somebody JB welded the oil temp sensor in my Saab and it doesn't leak, so it is possible. That's low pressure though.

 

This brings me to my next question: Where should I source a new block? Used engine? Salvage yard? Remanufactured engine? Jasper? Powertrain Products? somewhere else?

In my old 4runner I got a used 3vze from a reputable salvage yard, turned into a real headache and ultimately cost me.

 

OP just where are you located ? Check out your regional forums

It comes down to what the budget can afford. Used Engine Rebuilt local would be my first choice

If going used to just install you might pay more but I like to hear and see the engine running .

Ideal would be a part out from someone local.

I have had Good luck with Jasper Engines in the past Chevy and Ford time flies it has been years you get what you pay for.

 

A competent welder should be able to fix that. Have them weld a t-fitting on there so you can thread the stock oil pressure sensor back on and cap the other end.

 

I'm in California, near lake tahoe. 1st gen tacos are some of the most common cars around here. I'll check regional forums but will likely buy rebuilt for a warranty and hopefully problem free.

 

@Tour991 parts out Tacomas and 4runners in that area

 

Yeh there are def welders out there with experience to do this. A good engine rebuilder could fix it or knows a welder to fix it. There isn't a lot of pressure there anyway.

 

3vze engines are time bombs no matter where the come from lol. They were/are notorious for head gasket issues

@Tour991 lives in your area and might be able to point you in the direction of a new engine for your truck

 

Thanks, I'll reach out to them.

 

The cost to weld this 3.4 block would not be cost effective now if it was a Cat or Come apart or Detroit then yes .

engine removal strip the block clean and clean some more any needed prep work preheat the block in a oven do the welding post heat treating put all the engine back together ( at this point putting the used internals back would be foolish ) drop it back in the truck.

the hard part is matching the filler to the block so the thermal expansion and contraction are as close as possible .

That is why my first choice would be a local used engine rebuilt

 

Pm'd you