Pretty sure I have a cracked block here

[Matt Brandsema]

Hey guys,

So I have been working on this 2000 Chrysler 300M (I have made a few posts about it recently). I really think I have a cracked block here but I would like a second opinion from you guys if possible.

This is my girlfriends car. She overheated it BAD twice (one time was very VERY bad, and the other time was just regular bad). I was surprised when she told me this because the thing was still driving! (She said when it over heated very badly, it stalled and wouldn’t start back up)

So she has had problems with it ever since, it showed a LOT of signs of internal coolant leaks (Most notable is not holding pressure during a coolant pressure test with no external leaks) so I said, “Well it is definitely leaking internally, it is either the intake gasket or something more serious”

So with nothing to lose, I replaced the intake gasket. Put everything together and found that NOW the engine seems to be leaking coolant into the valley (I know this because coolant was coming out of the valley drain hole). Tore everything down again (valley was filled), redid the job and triple checked everything. Same problem.

I then did a leak down test and found that I had major leakage in one cylinder on both banks. I even heard and SAW coolant bubbling from around the intake valve (I could see the valve through the holes where the intake attaches to).

So I took a chance and hoped it was the heads causing all this mess (Another issue was white smoke out the tailpipe on cold start up, which I am sure was caused by the heads). Got two heads from a junk yard and put them on. Did another leakdown test to verify the parts and my job, and the heads passed the leakdown test with a max leakage of 18%. This told me that the top end of the engine is now in good mechanical health.

Put everything back together, triple checked my work and it is STILL leaking into the valley. I even got the lower intake resurfaced fearing I may have marred up the mating surfaces (Didn’t get the heads resurfaced though. But they looked fine.).

Pressure tested the cooling system and it is still not holding pressure.

My only conclusion is that this car was hanging on by a thread after over heating twice, and tearing into it as deep as I did to get the intake off pushed it over the edge. I cannot think of any other way coolant would be leaking into the valley (Yes I torqued everything to spec and in the proper sequence). As I said, I triple checked my work multiple times. I am a VERY meticulous person.

Any thoughts?

Topic

[college man]

This is only way I know how to confirm the diagnoses.

[Matt Brandsema]

If only the block were cast iron. But alas, it is aluminum :[

[college man]

[quote=”Xyius” post=107346]If only the block were cast iron. But alas, it is aluminum :[[/quote]

try this.

[Its me]

Not so fast about a bad block…

Chrysler 3.5s are known to leak coolant in the valley…. The engine heat hardens and warps the o-ring sealing the heater tube at the front of the engine. Then the coolant then leaks into the engine well underneath the lower intake manifold, filling it up with coolant.

Take a mental copenhagen/smoke break… go out and check the O rings…

-Karl

[Matt Brandsema]

[quote=”ToyotaKarl” post=107385]Not so fast about a bad block…

Chrysler 3.5s are known to leak coolant in the valley…. The engine heat hardens and warps the o-ring sealing the heater tube at the front of the engine. Then the coolant then leaks into the engine well underneath the lower intake manifold, filling it up with coolant.

Take a mental copenhagen/smoke break… go out and check the O rings…

-Karl[/quote]

Okay so that o-ring actually has a story behind it.

When I FIRST took off the intake, I had realized that I had accidentally cocked the tube to one side when I was prying the hoses off the heater tube. I removed the tube and found that the oring was damaged. I then went on to the Chrysler site and ordered a new one. (The weird thing is the website only let me go down to 2001, the car is a 2000. Were the motors the same in these two years?)

Anyway I found the o-ring and ordered it, but upon getting it I noticed that the old oring was thicker than the new one. The new one just seemed like a normal o-ring where the old one seemed specialized for this purpose.

I was always concerned about this, and wondered why they would be different. Perhaps I should go to the dealer personally and have them order it? Maybe I should replace the tube entirely? It isn’t in the best shape.

[Lorrin Barth]

The two rules of relationships with girlfriends:

1. Tell her she is pretty

2. Never admit to any mechanical knowledge or abilities

I got married ten years ago to a school teacher who lived out of state. After the honeymoon the plan was for us drive her car back to where we were now going to live. It took me an hour of scrubbing just so I could see out of the windshield enough to drive.

[Author]

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