Auto-gurus... Blown head gasket???

[Gomer]

89 Dynasty 190K miles
3.0L V-6
head gasket and valve seals done @ 140K miles

Symptoms:
1. Bubbles in coolant/recovery tank. Cooling system is pressurized at cold temps. Bubbles were first noticed several months ago. Pressurization is a more recent problem.

2. Minimal coolant loss, but increasing. No obvious clouds of white smoke, but a small amount occasionally on startup. Very minimal.

3. Miss and power loss @ speeds above 55 mph. Not really a dead miss but making for poor highway driving. This is pretty recent over the past month and getting worse. Sometimes on long runs, the miss will go away for a short while. Acceleration is fine, all ignition components tip-top. No discoloration of spark plugs. Perhaps miss due to loss of compression?

4. No oil contamination.

I am pretty sure this is a head gasket problem. It has been slow coming on as I noticed the bubbles first several months ago. I am just curious as to what anyone elses opinion is on this before the heads are pulled. I am also worried that maybe I am dealing with a cracked head. Any thoughts on that? To the best of my knowledge, this particular engine and head gasket problems are pretty common. I am paying my way through school and this time of year is when $$ are at their lowest. If this sounds more like a headgasket than a cracked head I will probably have it taken care of. Otherwise I will have to seek another course of action as a head would probably be too expensive.

More than likely the car will be into the shop when I nurse it home from school this weekend. It is driving fine still except for speeds above 55 so it will get me by for a short bit. However, it is only getting worse and the pressuriztion is starting to get extreme. Just looking for some opinions from this wonderful wealth of knowledge known as SyOpt.community.

Thanks all

[krusty the klown]

You will not need to have the head removed just yet. A decent garage will be able to test the cooling water to determine whether it contains combustion products. A compression test will reveal if there's a problem... but it won't tell you exactly where (i.e. worn piston rings will give low compression, but you'll be burning oil as well). Has the engine overheated? Check for rust on the sides of the head (or white corrosion if it's alloy). Also check for evidence of coolant leaks - usually the coloured antifreeze is quite noticeable.

The head gasket went on my old Ford V6 and I was getting similar problems, including missing after stopping the engine hot for about 10 mins and restarting. Water from the pressurised cooling system was being forced back into the cylinder, causing it to miss until it was blown out.

Some white steam emission is normal from cold with a cold exhaust pipe... especially with gasoline engines.

Is the car used mainly for stop-start runs, or does it get a decent run most times? This can foul the plugs and cause missing... allthough you said that the plugs are not fouled...
Also, check the condition of the plug leads... are they covered in oil and dirt, or nice and clean? A layer of filth over them is a definate contender for misfiring. Solvent cleaner sorts this out, but it's also worthwhile looking for obvious sparking whilst the engine's running, as a lead could be damaged.

When the head gasket was done on mine, it did not cost a lot more to do both sides, as most of the labour charge was in removing the carb and inlet manifold, so it might pay to get both sides done if it's diagnosed with a blown head.

Good luck...!

[Sweeper]

3.0 liter engines are known for head gasket problems. Worked on many of them. The pressure at cold start up is from which ever cylinder is leaking accross the headgasket into the coolant. The miss, due to water on a plug causing it to miss fire or not fire at all. Which in turn causes power loss due to loss of a cylinder. Bubbles in the overflow tank. Cylinder pressure in the coolant. Have the system pressure tested as stated above while the engine is cold and hot.
Sweeper

[sharder8]

It's a blown head gasket alright!

I just replaced the head gasket on my '90 Honda Civic AWD Wgn. It took me a total of 3 hours and it is now running like new engine.

Mine went slowly like yours is doing, but one day, BAM, it went bad between cylinders 2 & 3.

Harder

[BBA]

Well...you won't do a 3 liter dodge in a couple of hours...thats for sure.

Definitely have the head reconditioned...valve seals and all. In fact, teh valve guides on that particular engine would sink into the head and cause smoking, power loss, rough running and all kinds of other problems. The fix is to use a special cutting tool dodge makes to put a groove into the valve guide material and put a snap ring in the groove...to hold the guide in place.

If you don't have them...you need them.

[Gomer]

Krusty...

No overheating, no external coolant leaks at the block. I can see evidence of a few small leaks at hose fittings, but that is the result of the pressure. This car is a work horse so it isnt the result of short-run fouling. Wires were the first thing I replaced in trying to resolve the miss. Cap and rotor are in fine shape as well.

BBA...

I am familiar with the 3.0 valve seal problem. I know the seals were replace at 140K and I am pretty sure the valve guides were modified at that time. I will have them checked though when they have the heads off.

Right now the shop I usually frequent for large jobs quoted me $620 which I don't think is too bad at all for the 3.0 in a dynasty. The shop I used to work at before (light mechanical/clerk) quoted me around $800. This is the shop that did the head gasket and valve seals on the car at 140K. That was prior to me obtaining the car from the owner of the shop. He is out of town right now but I am going to try to get ahold of him and see what he can do for me.

Again, thanks for all the input. I apprecaite it. And feel free to add whatever you think may be of help to me.



[This message has been edited by Gomer (edited 04-17-2001).]

[Gomer]

Well I see the consensus is a blown head gasket. Before I take it in, is there any any other place that the pressure and air in the cooling system could be coming from?

[Gomer]

Thanks caddmannq. I had considered all those, I guess I meant something simpler then a head issue. As for the re-torqueing of the head bolts, no they were not. I will bring that up with the guys at the shop when I drop the car off Friday.

[Gomer]

2 cracked heads, may be put to pasture. Rebuilt tranny only has 25K on it though. Decisions, decisions.

[skai]

Gomer when the head was done was it because the engine overheated?Alloy heads when overheated become soft and lose tourque as Cadd said check the hardness should be above 75 rockwell.skai

[Richard_Cranium72]

Or,, the head gaskets may have been some off the wall "Non-OEM" Autozone junk.

Or, the deck surface may have needed surfacing and finally blew the gasket.

[Gomer]

Richard you missed my most recent post.. 2 cracked heads.

Story of car.

3 or so years ago I worked at a garage. The car belonged to a regular customer. With 145,000 or so miles on it, the head gasket blew (not overheated) and it was burning oil something fierce due to the faulty valve seals. In the 6 month time span prior to this, a lot of money was put in the car. Complete brakes all around, rack and pinion, PS pump, 2 axles, a hefty chunk of change. When the head gasket went the owner saw the light and decided to purchase a new car. So the owner of the garage obtained the dynasty (at what price I know not). He had one of the guys in the garage do the seals and headgasket. He then put the car up for sale. I was driving an 86 celebrity at the time with 205K on it. I endend up with the Dynasty for $1,700. The body of this car was in beautiful as it stil is now. The tires on it were in pitiful shape so I yanked the four off the celeb and threw them on the dynasty. Sold the celebrity for $500.

45,000 miles later here I sit with 2 cracked heads. My guess is with 190,000 on them they were fatigued. The fact that the guy doing the sidejob for the owner wasn't too worried about a comeback and wanted to get it done as quick as possible. Actually, that may have played a big part in it. Lacking anyway of proving this, I have no recourse with the owner of the garage. Heck, it's been 3 years, 45,000 miles.

Such is life. A big problem is I am paying my way through college and this is the time of year when savings hit rock bottom (I recharge them over the summer). I also found out yesterday that I have torn two ligaments in my thumb. Start PT today. When it rains it pours I guess.

Thanks again for all the input.

[Richard_Cranium72]

There is some stuff you can put in the engine to stop the leaks on cracked aluminum, Liquid Gold is the local name.

It is a clear liquid with gold flakes lying in the bottom, drain ALL anitfreeze and run with it and water ONLY.

Works pretty good, I used it on a SOHC GM 2.3

Another way is to take the heads off, I got to get ya the info on that stuff, I looked it up last year.

Lemme know