[DMCForum] Re: damnit to hell (my poor engine)

["Matt Spittle" <mds328@xxxxxxx>]

Some really great tips here, so thanks for that.  I pulled the heads 
off the car today and they're being sent to Rob Grady to check 'em 
for warpage.  When I get them back and installed, I'll do the 
pressure tests as your describe.

While I was pulling the motor all apart today I found a few more 
vacuum leaks.  Namely, the o-ring on the cold start tube was shot, 
there was NO o-ring underneath the fuel distributor, and the o-ring 
on the ignition distributor was also shot.  And yes, the o-rings on 
the Y-pipe were also shot, so that might have explained the coolant 
in the valley.

Are all car engines like the PRV?  That is, with the possibility for 
vacuum leaks every single place you look?

Matt
#1604

--- In DMCForum@xxxxxxxxxxxxxxx, "therealdmcvegas" <dmcvegas@xxxx> 
wrote:
> 
> --- In DMCForum@xxxxxxxxxxxxxxx, "Matt Spittle" <mds328@xxxx> 
wrote:
> <SNIP> 
> > Will running a coolant pressure test verify if I have a blown 
head 
> > gasket?
> > 
> > thanks,
> > 
> > Matt
> > #1604
> 
> Most definetly. You'll be pressurizing the cooling system, and 
forcing
> water out of any leaks that you have. I had lots of coolant in the
> "Valley of Deat" too, when one of the O-Rings on the Y-Pipe finally
> rotted away, and allowed fluid to flow out freely. So you'll want 
to
> snag a couple of new rings down at the local autoparts store when 
you
> pick up the pressure testing kit. BTW, don't bother looking for the
> rings in the aisle. They're in a box behind the counter.
> 
> But first, let's talk about what causes a head gasket to 
prematurely
> fail. Heat is the enemy here. And you know that if you severely
> overheated an engine, the cylinder heads warp and seperate 
themselves
> from the headgasket. Obviously at that point you need to replace 
both
> the cyliner head, and the head gasket. But, there is also another
> silent killer of headgaskets, and it too is caused by heat.
> 
> Improperly bled cooling system: That's right. If you've got air in 
the
> engine, you're gonna SEVERLY shorten the life of the headgasket. It
> works like this. Cast Iron cylinder sleeves will heat up and expand
> and a far slower rate than the Aluminium cylinder heads. However, 
when
> we have coolant flowing across them both, the heat is gently
> transfered between the two, and they both heat and expand at a much
> more syncronized rate.
> 
> But air inside the cooling system negates all this. Water doesn't 
flow
> across the surfaces evenly, and pockets of air them become steam
> pockets. Now keep this in mind: Steam is a gas so it rises, and 
it's
> the aluminum cylinder heads up that are on the top. The water below
> may only be like 120°F during the warm up, but the steam pockets 
have
> already hit 260°F+! So the Aluminum expands much more quickly than 
the
> Cast Iron below. What happens here is that the head gaskets are 
slowly
> torn, because the two sides between it are shifting in different
> directions.
> 
> And DeLoreans are tricky to the average mechanic, when it comes to
> diagnosing bad headgaskets just by sight.
> 
> Because of that damn valley under the intake manifold, it's easy to
> believe that the car has a bad head gasket. You leak out fluid, 
but it
> never drips below the car. Instead, it collects up above, and gets
> boiled off. And then when a car isn't always run up to temperature,
> the condensation inside is easily mistaken for coolant in the oil.
> Although I too have concerns about that crap in the oil filler cap 
for
> your engine.
> 
> Do this:
> Step 1. Pressure test a FULL cooling system. 14½ PSI for 15 
minutes,
> and the fluctuation should be minimal, if at all.
> 
> If no leaks detected, move on to step 2. If leaks are found, repair
> them before proceeding. Remeber, you're dealing with coolant 
hoses, a
> radiator, engine block, AND the heater core inside. So check all 
these
> areas IF the pressure isn't able to maintain itself.
> 
> Remove the rocker covers, and pull the oil drain plug. See if any
> water sprays, or otherwise visably drips out of any of these 
places.
> That'll find out what's going on with the engine.
> 
> Step 2: If/when no leaks are present, reassemble the top end with 
new
> seals, hoses, etc. Use silicone hoses for the water pump, new 
rubber
> tubes for the vacuum lines, new orings for the intake manifold, new
> oil resistant hoses for the breather tubes, etc. SEAL EVERYTHING! 
Make
> certain that there are no vacuum leaks.
> 
> Step 3: Disconnect the Oxygen sensor from the ECU wire, so that the
> engine will stay in "limp mode", and won't fiddle with the O2 
mixture
> on you. Start the engine, and see how she runs. Since you had 
vacuum
> leaks before, you're prolly gonna need to adjust the CO mixture to 
get
> the car running right. So if you need to fiddle with it right now 
to
> get the car running right, that's OK.
> 
> Step 4: Once the engine is cool, flush it with this (2nd from the 
bottom):
> http://www.berrymanproducts.com/Default.aspx?tabid=139
> This is POWERFUL stuff. It dissolves anything (including 
styrofoam),
> and will clean out your motor. You'll only need about &#8532; of 
the bottle.
> Pour it directing into the crankcase, and idle the motor for about 
7
> minutes. Then shut the motor off, and drain the oil & cleaner out 
ASAP.
> 
> After that you can drive the car to your local old skool Volvo
> mechanic where you can reattach the O2 sensor, and get the CO 
balanced
> on the motor. But I would first add that you pour some Techron into
> the tank, and burn out the old gasoline first, and refill with 
fresh
> before tuning the CO on the car.
> 
> -Robert

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