CyprusMustang

#1
Today 03:34 PM by CyprusMustang
Ok so I did a c4 to AOD swap. Car has been sitting for 3 years. I've also changed radiator, few hoses and couple other things.

Now I start the engine for first time after three years and after warming up for about 15-20 min and engine reaches it's running temp I get this knocking noise and jerking of the coolant hoses.

So I let cool down a bit and out of curiosity I do a compression test. All cyl are running around 160 give or take. All plugs show unburnt fuel ( my engine running rich) and no water in oil.

Now I put everything back and let cool down completely. I fill radiator to about an inch of visibility and start engine with no cap on. After 15-20 min when car reaches running temp, the knocking begins and the coolant begins to overflow out of the radiator.

Does this mean my head gaskets need replacing?

Also, on another note my engine is running rich ( prob I always had) and I get water out my tailpipes even after 15-20 min of warming up.

Any thoughts???

CyprusMustang

Anyone? I'm getting few views but no comments... Anyone know anything?

88 orangepeel notch

I'm assuming that this is a 302/351. Does the thermostat open and the fluid circulate? As in visually seeing it circulate with the cap off.

It would be odd that a head gasket go bad from sitting. Especially since its iron heads on an iron block. But to be sure, they do sell these test strips that you dip in your coolant that tests for hydrocarbons. A sure sign of a bad head gasket.

CyprusMustang

When the cap is off and i rev the engine from the carb I can see the water level drop by 1/4 inch and then raise again. I'm assuming that is the water pump working. I changed the thermostat las week I installed a new one (195) to make sure it wasn't the problem. And yes I have a small hole in the stat for the circulation.

I also tried to bypass the heater by joining the two hoses to make sure I have no blockage.

I have an aftermarket intake with water passage for cooling. It starts to make pinging gurgling noises around 150-160 degrees and starts to spill over. Then stops, then starts spilling on and off. At that point I switch off car as i don't want to cause further damage.

88 orangepeel notch

I'd use those test strips then and check for a blown head gasket. You can get them at your local auto parts store.

I'm assuming you got all the air out of the system first after the new rad. and hoses.

Just curious, when you say pinging, do you mean pinging as in detonation, while your driving ?

CyprusMustang

Ok update,

Since I have nothing else to do but wait for my new spark plugs I decided to test the old ones.

Cylinder 3 spark has no reading on the multimeter so it's 100% shot. Cylinder 7 has a high reading 7500 on the 20k setting and it's showing its not 100% grounded so I'm assuming it's on its way out.

So my engine was running with one cyl less and one cyl poor. Could this cause a problem with the coolant and knocking noise??

They dont sell those strips or other test here. Have to order it online. First things first Ill try to get the engine to idle first and then take it from there. Maybe it will cure itself.....

CyprusMustang

I haven't taken the car out of the driveway yet as I want to make sure it's running smooth first. I live on a hill so if I break down further down the road I'll need a tow truck to get back..

The noise is like a knocking noise as the water kettle makes when the water reaches boiling point.

88 orangepeel notch

The bad plugs won't cause the overheating, it'll run rough, but won't hurt the motor.

Did any of the plugs you pulled look cleaner than the rest. If coolant is being burned in the combustion chamber, it'll actually clean off the plug. You'd also see white smoke out the exhaust though.

If the the head gasket is bad where it doesn't allow coolant in the cylinder, but actually let's pressure out into the cooling system. You'll get bubbles like your describing in the radiator. But you'll also see a black film on top of the coolant after awhile.

Good description on the noise, sounds like your describing the sound metal makes as it heats and cools. The way cast iron exhaust manifolds would "tink" when they cool down.

And yes your right, I wouldn't drive it till this problem is fixed. Good call

CyprusMustang

Ok so I don't get a bubbling in the radiator until about 150 degrees and i wouldn't say small constant bubbling, just every minute or two it'll boil over the radiator and an occasional popping up of water.

And I am not sure the engine overheats as I havent actually let it run up to 180-190 as at that point the noise will have already started and the coolant already making a mess on my floor.

Before I parked the car 3 years ago it ran ok. Engine was jumpy ( could have been spark plugs ) but never a prob with overflowing coolant and noise until now. As said before I have since then changed the transmission, torque conv, radiator, put an oil cooler, and other minor things but nothing to the engine.

All the plugs were same, carbon fouled and few smelled of gas. Perhaps the ones with the weak spark. That would cause the gas to seap down into the oil causing the smell of gas into the oil. But still the noise baffles me and have to wait for my sparks to try anything else .

I am hoping the knocking is the combustion or non combustion of the non firing sparks and the coolant is an air pocket?

CyprusMustang

Could even be the unburnt fuel hitting the exhaust. Never thought of that one.