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

["cartermartin" <cartermartin@xxxxxxxxx>]

This was a most interesting thread (the subject line right out of my 
lips). 

I am reasonably sure at this point I will have to reassess the 
condition of my engine (PRV/B280f in a...umm...Volvo...). 

I have some more questions:

1. How does one properly bleed the cooling system on one of these?

2. Would a compression test reveal a faulty head gasket? I have good 
compression on all 6 cylinders (180-185psi, maybe too good?). 

3. Would a head gasket that is bad or heading that way cause excess 
pressure in the cooling system? 

The engine is running strong but I have had a couple high 
temp 'incidents'. And chocolate milkshake in the oil filler which was 
there before though.

Carter

--- 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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