Crack in manifold at ECT sensor

[east302]

Truck is a 1998 with the 350. There is a hairline crack leaking coolant below the coolant temperature sensor.

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From the bottom lip visible in the photo, the crack extends about 1/16" down the housing.

How urgent do you think this is? Not sure how long it's been leaking. I just noticed it after swapping out the leaking water pump this weekend.


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[michael hurd]

Every time the cooling system is pressurized it will leak.

It is possible that the temperature sensor was threaded in too far.

What I would do. ( it is an older vehicle already )

Allow engine to cool. Remove some coolant and the pipe that is hindering access. Clean the area with brake cleaner, then with a small wire wheel... preferably stainless.

Coarse sandpaper may also be used. Clean after abrading the surface and apply JB weld liberally over the area and allow to cure.

JB quick would be my choice, but the regular product will work as well. Mix according to directions, spread with a wood popsicle stick or similar and allow to cure before refilling the cooling system.

 

[someotherguy]

Yep, JB the crap out of it. Cooling system only pressurizes to 16psi.

That crack was caused by someone thinking you have to torque the CTS down to seal it. They're pipe thread...it's self-sealing as it goes in; you don't have to go animal on it.

Richard

 

[east302]

Thanks guys, will give it a shot.

That "someone" was me...didn't realize it only took 10 ft-lbs when I replaced it a few months ago. Should've looked up the spec first.


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[east302]

Well no dice on the JB Weld, it's still leaking but it was worth a shot. The crack extends about halfway down the threads on the inside of the sensor housing. Guess I'll add a new intake to the "to do" list. Couple of questions if you don't mind...

1. Rockauto sells an AC Delco lower intake...is there another brand that would be worth considering?

2. Should the upper intake be replaced as well? It's original to the truck, 190k miles, but no indication of any cracks or leaks there.

3. Is the MFI swap worthwhile since I'll be in there? Any opinion on the AC Delco vs Delphi kits? I'm pretty sure that the catalytic converters are damaged, so any prolonged moderate to heavy acceleration results in it bogging down. Merging onto an interstate is fun. No CEL, but it smells like gas in the mornings. Averaging 10-mpg. Delco plugs and wires have about 50k on them, fuel pressure checks were in spec and the filter is good. Oxygen sensors are original and I don't have a scan tool...

4. Which leads me to this...the DashCommand from Palmer Performance says it will read the cam retard. Can anyone confirm or recommend another inexpensive option?

 

[michael hurd]

Mark the distributor well on both the manifold and the position of the rotor. Transfer the mark on the old lower intake to the new replacement before installation.

You can use a pair of vernier calipers or similar to make sure you get the mark in the same place.

If the engine is higher mileage, you might consider replacing the injectors at the same time.

If the converters are toast, you would be best served to replace them before anything else... including changing the injectors.

 

[east302]

Thanks, I'm hoping I can get the distributor back into the original position the first time. If it were in the front like a Ford, that would make it so much easier.

I replaced the catalytic converters about three years ago and it solved the driving issue immediately. Unfortunately, I didn't address whatever damaged them in the first place so I've ruined the new ones now. I need to resolve that once and for all.

Anything else that should be replaced while I'm in there?

 

[michael hurd]

You could replace other items, but you have to ask yourself, is it worth it?

When you have excessive slack in the timing chain set, it leads to inaccurate timing, and the factory timing is conservative.

How many miles on the engine?

 

[east302]

It's my daily driver, so while I wouldn't want to go overboard replacing parts unnecessarily, I do want to keep it in good shape for the foreseeable future. If the 350 ever gave out, I'd replace the engine. I couldn't picture selling it, in other words.

I considered pulling the timing cover when replacing the water pump (the crank seal is leaking) but didn't get into it.

It has almost 190,000 on it.

 

[michael hurd]

If there are no signs of issues with the injectors, I would be tempted to leave them as is.