Hello,

Time to fix the engine.

- Quite browned coolant (level ok, no leak), dirty and a little bit oily
- Engine oil at recommended level 10W40 synthetic (leak 1quart every 2
months at the main seal but will get fixed new oil pan gasket and main seal)
- Radiator blades are clean,
- Fan rotating ok, and factory fitted to the radiator.
- Overheating was not an issue until this summer (got it to vapor lock
because of coolant boiling in the following conditions: 1979 Camaro
Berlinetta 1.6 metric tons + 4 passengers 250 Kg [total 1.85 t] 2 US
ton, 15km (9.32miles) ramp up at average 4%, 32°C outside temp 90°F,
larger tires than factory (255/60R15 rear, 235,60R14 front) with factory
3/23 rear transmission.
These where hard conditions for an old engine but it should not have
gone to the point of boiling the coolant. (Hopefully I didn't engage the
air conditioning compressor because it need upgrade and refill)

From web searching, these may reveal a possible exhaust gas leak into
the coolant because of cracked head gaskets (coolant color change and
overheat). Do you agree with that diagnosis?

I'll have to wait until September, for a mechanic to look at it but,
would like to order replacement parts now, because of significant lag in
delivery to Europe.

If head gaskets need to be replaced, what kind is suitable for a 30yo
stock unmodified GM factory LM1 who went over the 5 digit km counter at
least once)?

There are many kinds of head gaskets listed with different thicknesses,
materials rated applicable for this 1979 chevy 350cid V8 (AKA LM1).

Are these gaskets ok?


--
Léa Gris

In article <4a86d555$0$22641$426a34cc@news.free.fr>,
Lea Gris wrote:

Quote:

From web searching, these may reveal a possible exhaust gas leak into
the coolant because of cracked head gaskets (coolant color change and
overheat). Do you agree with that diagnosis?

Possible
I'd flush the system out with clean water and check the thermostat first.
See what happens.
Is the Rad cap ok?
Belts not slipping?
Maybe change the stat anyway. I've had one that appeared to work in my LT1
but changing it cured some weird symptoms.

Not sure what thickness gasket your motor should have but those are
probably fine. Ask summit what they'd reccomend.
You'd also need the inlet manifold gaskets as well.

HTH

--
Terminal_Crazy

Mitch - 1995 Z28 LT1 M6 terminal_crazy@sand-hill.freeserve.co.uk
Lancashire England http://www.sand-hill.freeserve.co.uk/terminal_crazy/

On Aug 15, 11:33 am, Lea Gris wrote:

Quote:

Hello,

Time to fix the engine.

Perhaps. But the first thing is to completely clean and fix the
cooling system.

Quote:

- Quite browned coolant (level ok, no leak), dirty and a little bit oily
- Engine oil at recommended level 10W40 synthetic (leak 1quart every 2
months at the main seal but will get fixed new oil pan gasket and main seal)
- Radiator blades are clean,
- Fan rotating ok, and factory fitted to the radiator.
- Overheating was not an issue until this summer (got it to vapor lock
because of coolant boiling in the following conditions: 1979 Camaro
Berlinetta 1.6 metric tons + 4 passengers 250 Kg [total 1.85 t] 2 US
ton, 15km (9.32miles) ramp up at average 4%, 32°C outside temp 90°F,
larger tires than factory (255/60R15 rear, 235,60R14 front) with factory
3/23 rear transmission.
These where hard conditions for an old engine but it should not have
gone to the point of boiling the coolant. (Hopefully I didn't engage the
air conditioning compressor because it need upgrade and refill)

Four passengers and 32 degrees uphill can be quite a load. Perhaps
more than an unmaintained cooling system can handle.

I don't know standard factory tire fitment for Camaros; I imagine
something like FR70-14. Tires may be a bit oversize but not terribly
so. Should not make any difference.

Quote:

From web searching, these may reveal a possible exhaust gas leak into
the coolant because of cracked head gaskets (coolant color change and
overheat). Do you agree with that diagnosis?

Not really. It is much more of a problem with heads/blocks with
different materials, specifically aluminum (heads) and cast iron
(blocks). Aluminum expands more than cast iron, so gasket is sheared
(a small amount) every time engine warms up and cools down.

Quote:

I'll have to wait until September, for a mechanic to look at it but,
would like to order replacement parts now, because of significant lag in
delivery to Europe.

First thing is to clean cooling system and change coolant. When was
the last time it was changed? Must be ten years or more! I have never
seen rusty, oily coolant and I have been lazy about cooling system
maintenance myself.

I suspect that the radiator may be a bit plugged, which will cause
overheating under heavy load. A bad head gasket will cause overheating
and bubbles in the radiator and coolant tank even in normal operation.

Are you losing any coolant, or is the level in the tank staying at the
same place?

If you are losing coolant, and can not find a leak anywhere, then
maybe you have a gasket problem after all.

If you are not losing coolant, then I would NOT start with an engine
overhaul, but with a cooling system overhaul.

--remove all the old "coolant"; it's bad already
--flush out the engine block and heater core
--have a good radiator shop look at your radiator; a bad radiator will
cause overheating as you describe; you may need a new radiator, and I
would recommend that if the existing radiator is original and looking
corroded
--replace all hoses (this will likely require a special order but
shipping will not be TOO bad I hope)
--if your fan is a clutch design (spins freely, has a big aluminum
disk in centre) make sure it is working properly; although bad fan
usually causes overheating in slow driving or stopping, a bad fan does
not make much difference in faster driving
--do you have a temperature gauge, or just a "HOT" light? you should
have a gauge to really understand what is happening at your engine
--maybe the thermostat needs replacement; I would go with the factory
recommendation which is probably 195F or 91C

Quote:

If head gaskets need to be replaced, what kind is suitable for a 30yo
stock unmodified GM factory LM1 who went over the 5 digit km counter at
least once)?

My old 1979 Firebird went 425,000 km. We had to remove one head to fix
a broken exhaust manifold stud; otherwise the engine was never apart.
Okay, that was a Pontiac 301 engine, but I would figure a Chev 350
will last a long time too. Honestly, if you are going to start pulling
the heads off to replace the gaskets, why not take the engine out and
do a full rebuild? Chev 350 parts are cheap (in North America) and
should not be impossible to find in Europe. Maybe a US or NATO base is
close by you?

.....Ed

Ed Treijs wrote:


disemboweled last year. I replaced both upper and lower hose with proper
factory design repros with proper turn around the AC compressor (for upper).


gauge did not reach the red zone but stayed near between 200 and 220°F
after the first 40Km. Quite hot but the highway here has long ramps and
turns between Millau (famous bridge) and Marvejols. Reference operating
temperature should be between 180 and 190.




hobby collector car and not my daily commuter. It runs like 500Km/month.


last owner did not use the car that much as he spent most of the 8 years
he owned it filling legal requests and forms, and paying insane amount
for dynos (required by legal registration), brake metering, and master
cylinder side clear transparent canister to get oil level visible
(required by registration), to have it registered legally in France as a
collector So he drove the car like 2 and half a year. Finally after
spending significant insane amount on legal nightmare and too little on
real restoration parts, and beside it ended right, he sold it to me






and the red zone between 220-240 upper mark of the gauge..

The 1979 Chevrolet service manual tells the normal operational
temperature is between 180°F and 190°F and the water thermostat should
open at 180°F.


pistons, piston rings, all shafts bearings at the size required for an
unmodified 1979 chevy small block.

Luckily there is a good mechanic nearby with the tools and knowledge to
do the engine rebuild. The car will go to his garage tomorrow for an
overall look and evaluation. The rebuilt itself and all the new parts I
bought will be done during October.

--
Léa Gris

On mine, it was oil coming from the transmission that get in the
radiator. This cause exactly the same symptoms as you.

How is the oil in the engine? If it look clean, maybe you got the same
problem as me.

Ed Treijs wrote:


My Camaro is at the mechanic shop. The oil pan has a crack to be
soldered fixed. Radiator and coolant circulation will be checked purged
fixed.
The work's going on it. I'll keep you tuned.

--
Léa Gris