Replacing Lambda Sensor Switch et. al.

[mluder]

So I am beginning my engine rebuild.

When installing fittings which have no gasket, seal, etc. like the lambda sensor switch or the thermal vac switch on the y-pipe is there any sort of dressing needed or do they go on dry?

Cheers
Steve

[DMCMW Dave]

Tapered seat fittings (lambda switch) and copper ring fittings (oil light switch, block drains etc.) go on dry. Pipe thread fittings (like the oil sender) will benefit from some teflon tape.

[mluder]

Tapered seat fittings (lambda switch) and copper ring fittings (oil light switch, block drains etc.) go on dry. Pipe thread fittings (like the oil sender) will benefit from some teflon tape.

Thank's, Dave. Thank God you guys "work" on the weekends.:smile:

I never even noticed it was tapered. I'll keep an eye out from here on.

Cheers.
Steve

[mluder]

Tapered seat fittings (lambda switch) and copper ring fittings (oil light switch, block drains etc.) go on dry. Pipe thread fittings (like the oil sender) will benefit from some teflon tape.

BTW - Issume you just tighten the tapered ones until finger-ish tight and then a little extra? Example the thermal vac switch on the y-pipe wants to point to the rear. So thighten until tight and then to propper position?

Cheers
Steve

[David T]

You have to be careful with switches that depend on the threads for an electrical ground. Too much sealer or teflon tape could insulate it. On tapered pipe threads there is no torque spec. You tighten it till it doesn't leak or by experience till it's tight. To tight and you can crack what you are putting it in. Like a wedge it gets bigger the more you screw it in. Brass stuff is kind of self-sealing so it can go in dry. It deforms to the threads and seals better than steel.
David Teitelbaum

[Chris4099]

Get a coolant pressure tester. That way you can fill the system and pressurize it. If you find any leaks, you can address them before you have the whole top end put back on. Also for the electrical sensors, put a meter across the sensor case and engine ground to verify it's not an open circuit from too much sealant/tape.

[mluder]

Get a coolant pressure tester. That way you can fill the system and pressurize it. If you find any leaks, you can address them before you have the whole top end put back on. Also for the electrical sensors, put a meter across the sensor case and engine ground to verify it's not an open circuit from too much sealant/tape.

Thanks, Chris.

Can I rent a coolant pressure tester from Autozone? Is it pretty strait forward?

Steve

[Chris4099]

I think this is the one from Autozone, but I've never used it before:
http://www.autozone.com/autozone/accessories/CST-Pressure-Tester-Adapters/_/N-263r?itemIdentifier=84330_0_0_

Just hook up to the expansion bottle and pump up to no more then 15PSI. With the system cold, it's actually more likely to show leaks then when warm (since the pipes haven't expanded yet making the clamps tighter).

[jawn101]

I think this is the one from Autozone, but I've never used it before:
http://www.autozone.com/autozone/accessories/CST-Pressure-Tester-Adapters/_/N-263r?itemIdentifier=84330_0_0_

Just hook up to the expansion bottle and pump up to no more then 15PSI. With the system cold, it's actually more likely to show leaks then when warm (since the pipes haven't expanded yet making the clamps tighter).

That's definitely the right tester from Autozone. They loan it. I have borrowed the one in my town about 10 times. In fact, it's still in my garage right now. It is a really well made tool, too! You can use it to test your cap as well as your system.

[mluder]

Don't you pretty much have to have everything back together to maintain pressure in the system or can you do it with out installing the intake manifold and the fuel distributor?
How does the tester work? You hook it up to the overflow bottle and manually add pressure with the pump to 15 PSI?

Sorry, about the stupid questions - I've never done anything like this before.

Cheers.
Steve

[Chris4099]

Only the cooling system has to be completed. Just fill the system with coolant and connect the tester to pressurize the system. You can then monitor the pressure gauge to see if there are any leaks (assuming you don't see any obvious signs of dripping coolant). If you don't have an auto bleeder, you can also bleed most of the engine side at the same time. Just crack the bleed nipple and it will force the air out on top without having to run the engine. From your FB page, it looks like you still need to add the thermostat housing and expansion bottle. But once done and coolant topped off, test away! You'll be happy you did if you discover a leak in the VOD while the the intake is still off!

[mluder]

Only the cooling system has to be completed. Just fill the system with coolant and connect the tester to pressurize the system. You can then monitor the pressure gauge to see if there are any leaks (assuming you don't see any obvious signs of dripping coolant). If you don't have an auto bleeder, you can also bleed most of the engine side at the same time. Just crack the bleed nipple and it will force the air out on top without having to run the engine. From your FB page, it looks like you still need to add the thermostat housing and expansion bottle. But once done and coolant topped off, test away! You'll be happy you did if you discover a leak in the VOD while the the intake is still off!

Yep - Bought coolant today and was planning to install the collant bottle and thermostat tonight so I'll stop at Autozone on my way home. I definately like the idea of testing before I put everything else back in.

I'm looking forward to Saturday - Hopefully I won't have to have my car transported there by AAA. :thumbup:

Cheers.
Steve

[mluder]

Only the cooling system has to be completed. Just fill the system with coolant and connect the tester to pressurize the system. You can then monitor the pressure gauge to see if there are any leaks (assuming you don't see any obvious signs of dripping coolant). If you don't have an auto bleeder, you can also bleed most of the engine side at the same time. Just crack the bleed nipple and it will force the air out on top without having to run the engine. From your FB page, it looks like you still need to add the thermostat housing and expansion bottle. But once done and coolant topped off, test away! You'll be happy you did if you discover a leak in the VOD while the the intake is still off!

Thanks, Chris. I rented the coolant pressure tester from AutoZone. I had a huge leak kfrom one of my NEW hoses. Huge pain to replace it because I had to disassemble half of the system and ended up with a valley full of coolant which is how I got here in the first place. Once that was fixed I found annother couple of small leaks. One jsut needed the hose clamp tightened. The other is at the thermostat swith in the water pipe on the drivers side. THe 30 year old gasket around it is cracked. I've ordered a new one but am probably going to MacGyver something together in the mean time.

Anyway - Kudos to you for suggesting the pressure tester. It would have been a nightmare without.

Cheers
Steve

[Chris4099]

Glad to hear you found those leaks before putting everything back together! Back when DMC-NW had their grand opening, they were doing free inspections. I was surprised to see how many leaks I had with so many of the new hoses I had put in the previous year. Once the system was warmed up, the pipes expanded and sealed up tight so I never noticed the leaks. However, I would still lose a few drops of coolant during start up.

[DMCMW Dave]

When replacing the hoses, are you guys doing anything to clean the aluminum tubing before you install the new hoses? The hoses do not bond well to corroded aluminum.

[mluder]

When replacing the hoses, are you guys doing anything to clean the aluminum tubing before you install the new hoses? The hoses do not bond well to corroded aluminum.

Dave.

I kept the hoses connected to the aluminum pipes under the car. The two aluminum pipes in the engine bay I pulled out, cleaned the corosion with a scotchbrite and dremel where necessary. Then High heat primer and high heat aluminum color topcoat. The hoses heading from the pipes back to the water pump are the originals. I cleaned them up too before reinstalling.

The new hose that had a hole in it was one of the short hoses that comes out of the top of the water pump (driver's side) and goes into the engine. I think it got bound on the hose clamp somehow as it had gouges where the clamp had chewed it a bit tough it wasn't in the area where the clamp actually goes. I was really surprised it went through becaus the damage looked so superficial. I probably made it worse trying to bend the hose into place to attach it.

Cheers
Steve