3400 Misfire and temp increase - HG?

[Tbay99Venture]

Now I need to plan for everything else I need/want to replace while I'm in there. Things like the timing chain (137k on the engine, might as well), O2 sensor, plugs again, thermostat... Anyone else have any recommendations for parts to replace while I have it torn down?

Not on the engine per se, but if you have the rear climate control option there's no better time to reach the heater hoses & tees. The forward heater core has an oversize diameter tube and a regular size one. Might want to make sure the plastic shift cable socket isn't about to wear out as well. What did you decide about the crank sensor wires?

[bszopi]

Yeah, I know, as it indicates the intake port, which cross over the engine.

Anyway, just got a call from the machine shop. He extracted the broken exhaust stud, repaired the spark plug hole, and replaced the valve seals. He also checked for flatness and he was really suprised to find them perfectly flat. He said he almost always has to mill down 60V6 heads to get them flat. Checked them all out overall, and says I should be good to go. Doesn't look like I'll get them picked up today, but definitely tomorrow.

Now I need to plan for everything else I need/want to replace while I'm in there. Things like the timing chain (137k on the engine, might as well), O2 sensor, plugs again, thermostat... Anyone else have any recommendations for parts to replace while I have it torn down?

[Tbay99Venture]

Hate to post something that may already be obvious, but just in case...

You'll probably find the cylinder numbers cast in the LIM have the odd cylinders to the front of the vehicle, contrary to the way the spark wires actually go.

[bszopi]

Ended up tearing it all the way down, and will be taking both heads to the machine shop tomorrow to get worked on. It appears that the spark plug in #2 wasn't the only thing potentially leaking. Had a broken exhaust stud there was well, and its inside the head, so I'll get to give the machine shop even more money....

[BLADE]

Is there a foreign object in that cylinder ???

[BLADE]

I had a helicoil in a truck and the spark plug stuck in it and broke the plug off in the head donot recomend a helicoil or definitly use antiseze on the plug and watch the torque

[bszopi]

Anyone ever helicoiled a spark plug hole at home? I'm contemplating it, as the new spark plug appeared to be leaking as well. So I tore it all down. I've got the front head off, still need to take the plugs out to look at the hole better. Just trying to decide if I want to try to do it myself, then put it all back together tomorrow, or take the head to a machine shop to have them fix the hole, then reassemble Mon, and possibly Tues evenings.

I may need to source a new crank sensor wire as well, as the current one got in contact with the exhaust manifold. It doesn't look like it melted down to the wires, but the 2 insulations are definitely melted together. And of course, I broke all 3 crossover studs, so I need to get some of those as well.

[bszopi]

Well, this might explain some of the issues, including the toy train sound I was hearing...



Head doesn't look too bad... :crosses fingers:

[Tbay99Venture]

Well if you aren't losing water, and you've been seeing the temp problems get worse but still don't lose water then it's hard to make a case to do all the extra work.

Our vehicle had around 160,000 miles or so in 10 years and has always run Death-cool or the Prestone equivilant. There was crud behind the head gasket holes but the holes themselves weren't obstructed. However, we had replaced the radiator anyhow since the plastic near the return hose fitting was split. (The epoxy you can buy made a good temporary fix so we could go camping that weekend.) I got the radiator in place and then the lame J-shaped hose to the rear heater started leaking. Fix that and the craptacular plastic Tee snapped a week later. I thought I inspected the plastic pretty well so my new rule is don't trust the plastic. Sorry, way off topic. Just trying to give you a baseline that the cooling system clogs might not be the issue. We get hot weather here well through September but the old radiator never had problems keeping the temp needle in the bottom range even in city traffic with the A/C on.

You can certainly take the hoses off and see that it flows out as fast as the garden hose can supply it. Then you could also check via the pump inlet & see whether the pump impleller has broken free.

[bszopi]

Even though I really don't want to deal with it right now, due to a bunch of other crap going on, I may just say fuck it and replace the head gaskets anyway. I'm almost tempted to bring it in, as I just don't have the time to mess with it right now, but I just hate being raped by a mechanic, especially on something like this...

[Azrael]

It wouldn't hurt to try a coolant flush. Check and see if the radiator is hot from top to bottom. Clogged passages would obviously be cooler.

I just replaced my headgaskets. While there was no sludge in the overflow tank there was some buildup on the coolant passages on the old headgaskets.

[bszopi]

Could a clog in the coolant system cause the above to occur? When I took off the radiator cap the other day, there was some pretty good "growth"" on and around the relief spring. Just thinking if something like that started to clog the coolant passages, a cylinder could heat up in a hurry and possibly cause misfires. And the fact that the engine gets up to halfway almost instantly. I mean, its been close to 100* here for the past few days, so its going to take longer for it to cool down, but I don't think it should be taking as long as it is.

[bszopi]

I did the following, as stated in the linked thread:

Take the radiator cap off, unplug the coil packs and turn the engine over. If there is coolant spewing out like mad, it's a head gasket.

I cranked it over a couple times and no coolant came out, so I think that rules out the head gasket completely then? I really have no urge to replace it right now...

[mickaz]

How common is a coolant leak to the intake passages but not yet into the engine? (Trying to understand the low performance, but that doesn't answer the temperature issue.) You might get your LIM gasket replacement site article yet

since there is more pressure on the cylinder side of the leak, cooland will be forced out of the radiator cap or the pressure tank. you might see some coolant burning but if its a very small leak it will be hardly noticeable.

since coolant is pushed out the radiator it will have a harder time cooling the engine depending on the leak it can take days or minutes to happen, in my case it was minutes lol

you will not get a noticeable low compression with a compression tool. ( since you need to do it cold, then again depending on the size of the leak.

if some coolant does get into the engine it will be so small that it will not be enough to be seen. ( a clean spark plug or cylinder)

and performance wise, well you get the idea. air + gas + coolant = shitty acceleration.

So this was how my HG was blown. Internally but only to a water passage to cylinder.

Oh and if you did drive like this, a while Do both the headgasket, as you will have put a Big strain on them because of the high temperature of the gasses.

[Tbay99Venture]

How common is a coolant leak to the intake passages but not yet into the engine? (Trying to understand the low performance, but that doesn't answer the temperature issue.) You might get your LIM gasket replacement site article yet