Oil temp sender threads stripped

nrchap · 03-06-2014, 03:06 PM

Hey guys, so I'm new to these cars, I've been storing a friends '71 914 1.7 for the last 6 months while he's on deployment. I've been tracking a source of the leak and traced it to the oil temp sender. When I pulled it out I discovered the top two rows of threads just gone. The previous owner, the current owner, and me were all stationed together and are all good friends so I have the last 3 or so years of the cars history available and neither remember changing it. SO. Here's where I'm at. I found the new sender on here, I just don't know the best course of action to repair it.

That's where you come in. Old owner said he's heard a lot about it from a Porsche club he was in in Cali but never paid attention. Is it fairly common? Please help!

The cap'n · 03-07-2014, 07:37 AM

Let's be clear here. You're talking about the temp sender, the one installed in the plate on the bottom of the engine, right? The plate is steel, the sender brass. If the threads in the plate are bad, replace it. If the threads on the sender are bad, replace it. Use a new copper ring, tighten it well. Tightening it too much "could" break it, but it's pretty sturdy. By the way, "Cali" is a city in Colombia, NOT a state in the US. It's doubtful your buddy was in Cali. Using the term "Cali" is offensive to those of us who were born here.

The Cap'n

nrchap · 03-07-2014, 12:07 PM

Thanks for the advice and passive aggressiveness. I'm going to try to chase the threads when I get back from CALIFORNIA in a couple weeks. It never dawned on me in the 5 years I lived there nor my wife, nor my in laws who were born in CALIFORNIA that shorthand could be offensive to the natives.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

I hope you mean the temp sender on the bottom of the engine. As the Cap'n said, the part that threads into is replaceable. And even if you can't find a new one, you can probably cut the old weld-nut off and weld on a new one, or possibly even thread on another nut on the back side of it.

If it's the sender for the oil pressure light, up on the top of the case, that is harder. Because it threads directly into the case, and is under a lot more pressure (it can be 80 PSI when the engine is cold!) and can leak a whole lot more.

Oh--and Cap'n, to be fair, I know California natives who refer to our state as "Cali". It annoys me, but then again I'm not a native--and I'm easy to annoy about linguistic things. (No, sorry, "impactful" and "orientate" are NOT WORDS!)

--DD

nrchap · 03-07-2014, 02:12 PM

Here's the part that I'm talking about on the bottom of the engine. I've already ordered a new one but attempting to clean the threads or pulling anything else off of the bottom is going to be a pain, being a Jeep guy I don't actually own a jack low enough to get the 914 in the air.

porschetub · porschetub's Garage

Sump plate oil temp sensor ...right?,fit a new one as you have ordered but drop the sump plate and clean the brass out off the sump strainer plate plug thread with a thin flat blade screw driver and test the fit of the new one until it screw in easy,a little locktite sealer wouldn't hurt,clean your oil strainer and change gaskets @ the same time.
Good luck.

TheCabinetmaker · 03-09-2014, 07:54 PM

Quote:

Originally Posted by The cap'n

Let's be clear here. You're talking about the temp sender, the one installed in the plate on the bottom of the engine, right? The plate is steel, the sender brass. If the threads in the plate are bad, replace it. If the threads on the sender are bad, replace it. Use a new copper ring, tighten it well. Tightening it too much "could" break it, but it's pretty sturdy. By the way, "Cali" is a city in Colombia, NOT a state in the US. It's doubtful your buddy was in Cali. Using the term "Cali" is offensive to those of us who were born here.

The Cap'n

Born and raised in Cali, not offended.

I suppose "temp" sender as used ablve is offensive then, any real temperature would be offended by the term "temp". Heck you didn't even put a period after "temp", that really could offend.

You could try cleaning up the threads on the temperature sender, Use a metric die or do some filing with a fine triangular file. If the holder for the sender is bad, then run a tap thru it.

nrchap · 03-20-2014, 04:22 PM

Quote:

Originally Posted by porschetub

Sump plate oil temp sensor ...right?,fit a new one as you have ordered but drop the sump plate and clean the brass out off the sump strainer plate plug thread with a thin flat blade screw driver and test the fit of the new one until it screw in easy,a little locktite sealer wouldn't hurt,clean your oil strainer and change gaskets @ the same time.
Good luck.

I'm back in the state now and decided to go straight to work on this thing as soon as I got off the plane an hour ago. Now, how in the world does this thing drop? I see some connections near the transmission and I haven't wiggled far enough up to see whats in front. I've got a combined seven days off before I leave for California in April and I'd like to have this PITA running by then.

Also, thanks to everyone for staying on topic and helping me out with this.

The cap'n · 03-20-2014, 05:08 PM

I'm seeing the picture, but I don't see the oil temp sender (it should be installed in that round cover with the bump on it (to the upper right in the picture), held in place by 2 6mm bolts and sealed with 2 6mm asbestos filled copper crush washers). Would it have been inserted in the drain plug hole? If that's the case, be VERY careful with those threads. If they're damaged, I suggest a proper insert (Helicoil or Time Sert) to fix the problem right.

Let's talk about the sump screen,mentioned earlier. You're new to this and we don't want you to make a BIG misteke. Remove the nut, pull the cover and the screen, then clean everything well, including the sealing surface on the case. Install one gasket, the screen, the second gasket, and the cover. Install the crush washer (it's NOT a plain copper or aluminum ring!) split side toward the head of the nut. This keeps the asbestos filler out of the threads. Put the nut on the stud and tighten it to NOT MORE than 11 ft lbs! The stud goes into the center camshaft bearing boss, and they have a history of breaking when the nut is overtightened. That, my friend, puts you into the proverbial "world of hurt". You don't wanna go there.

The Cap'n

nrchap · 03-20-2014, 05:27 PM

Quote:

Originally Posted by The cap'n

I'm seeing the picture, but I don't see the oil temp sender (it should be installed in that round cover with the bump on it (to the upper right in the picture), held in place by 2 6mm bolts and sealed with 2 6mm asbestos filled copper crush washers). Would it have been inserted in the drain plug hole? If that's the case, be VERY careful with those threads. If they're damaged, I suggest a proper insert (Helicoil or Time Sert) to fix the problem right.

Let's talk about the sump screen,mentioned earlier. You're new to this and we don't want you to make a BIG misteke. Remove the nut, pull the cover and the screen, then clean everything well, including the sealing surface on the case. Install one gasket, the screen, the second gasket, and the cover. Install the crush washer (it's NOT a plain copper or aluminum ring!) split side toward the head of the nut. This keeps the asbestos filler out of the threads. Put the nut on the stud and tighten it to NOT MORE than 11 ft lbs! The stud goes into the center camshaft bearing boss, and they have a history of breaking when the nut is overtightened. That, my friend, puts you into the proverbial "world of hurt". You don't wanna go there.

The Cap'n

That hole is where I pulled the sender from originally and the new one absolutely would not go in by hand... Pleeeease don't let this be a case of someone half assing something 15 years ago.

The cap'n · 03-20-2014, 05:34 PM

If you want to reinstall the temp sender into that hole, find an appropriate thread chaser and give it a go. NOT a tap, as taps remove material you can't afford to lose. Thread chasers reform the threads. Before all that, take a good look at the threads and make sure they haven't already been repaired with an insert! That would present a whole different set of challenges.

The Cap'n

TheCabinetmaker · 10:14 AM

Quote:

Originally Posted by nrchap

I'm back in the state now and decided to go straight to work on this thing as soon as I got off the plane an hour ago. Now, how in the world does this thing drop? I see some connections near the transmission and I haven't wiggled far enough up to see whats in front. I've got a combined seven days off before I leave for California in April and I'd like to have this PITA running by then.

Also, thanks to everyone for staying on topic and helping me out with this.

the hole you show with no plug in it is the drain plug hole. The temperature sendor is supposed to go where the round metal plate (about two/ three inches diameter) is located. (shown in the top right of your photo) Note this is NOT the other large round plate that has the nut in the center!!

To do it as the factory intended, get a drain plug in the small hole, then buy a different metal plate for that big round hole, this plate is often called a taco plate. this new plate is designed to accept the temperature sendor, it will have a threaded bung on it for the temperature sendor. There will also be a second big round plate to serve as a protective cover for the part of the sendor that sticks out and the wire.

pcarcarerra · 03-26-2014, 01:38 PM

Oil temp sender goes under the plate (commonly called the taco plate) in the upper right of your picture. The hole you are showing is where the standard drain plug goes.

donporfi · 04:00 PM

These are the oil drain, sump plate and oil temp plate.

The oil temp sender plate should look like this, if that engine had the temp sensor. If it does not look like this one it did not have a temp sensor in that plate and probably you have a plate that is not prepared for a sensor.

Drain plug and sump plate should look like this

TheCabinetmaker · 03-28-2014, 08:11 AM

Quote:

Originally Posted by donporfi

These are the oil drain, sump plate and oil temp plate.

The oil temp sender plate should look like this, if that engine had the temp sensor. If it does not look like this one it did not have a temp sensor in that plate and probably you have a plate that is not prepared for a sensor.

Drain plug and sump plate should look like this

Pretty close but not exactly as stock, the plates should be painted black, the Phillips head screws should be hex head, there should be a cover plate over the temperature sendor, and I believe all the stock sendors had a male 1/4 inch press-on connector.

good photos however showing the general layout

nrchap · 03-29-2014, 03:06 PM

Thank you so much for the replies and clear layout guys. I had to order the thread chaser kit and it came in this week. I've been dealing with finishing my suspension and rear axle on my Jeep but finally figured the 914 out today. As I'm sure you've figured out by now, someone had jammed that 14 x 1.5 sensor into the drain plug hole which wound up being 12 x 1.5. as of about 15 minutes ago I ran the proper thread chaser up into it and met a little bit of resistance but was fine after that. I put the drain plug in, filled it up and took it around the block. It runs, it drives, it's back in my garage and will not move until he comes and gets this thing. I'm sending the new sensor with him and he can do with it as he pleases.

With all of that said, I'm going to miss this car. It's the first "sports" car I've regularly driven since I had my S2000. After we get settled into a place where we want to be for a while I'm going to start hunting for one.