Buick with leaking head gasket

[Snuffy "Hub Cap" McKinney]

This is more of a Sherlock Holmes type mystery than a practical matter.

Neighbor has a leaking head gasket in his Buick bad enough so that the engine runs rough all the time. Watch does with it is not my concern.

When driving it runs cool. When sitting idling the temp increases rapidly. If he puts in neutral and revs the engine, he says it drops to normal quickly. Radiator, fan clutch, thermostat, water pump all checked out and working normally.

I'm wondering .... when the engine is turning slowly, if the the coolant pressure drops, which could be letting more exhaust leak into the coolant and raise the temp? Says when the temp goes high, he can smell antifreeze, probably blowing out the overflow.

[gregz]

The exaust should do nothing. Might need radiator and system cleaned. ?

Greg

[micky]

A lot of cars run hot at low RPM. One guy had to shift into park at red lights and "race the engine" to cool it down. Didn't overheat on the highway. Probable clogged radiator or bad water pump. .

[bob haller]

On Saturday, April 18, 2015 at 1:45:46 AM UTC-4, Snuffy Hub Cap McKinney wr ote:

gine runs rough all the time. Watch does with it is not my concern.

y. If he puts in neutral and revs the engine, he says it drops to normal q uickly. Radiator, fan clutch, thermostat, water pump all checked out and w orking normally.

pressure drops, which could be letting more exhaust leak into the coolant a nd raise the temp? Says when the temp goes high, he can smell antifreeze, probably blowing out the overflow.

most head gasket leaks crate white exhaust.

if coolant leaks into oil engine will soon be siezed

[clare]

First question - what year and model???

If it has a leaking headgasket, nothing else matters. It NEEDS to be fixed (or thecar scrapped)

[Tony Hwang]

+1

[trader_4]

engine runs rough all the time. Watch does with it is not my concern.

idly. If he puts in neutral and revs the engine, he says it drops to norma l quickly. Radiator, fan clutch, thermostat, water pump all checked out an d working normally.

nt pressure drops, which could be letting more exhaust leak into the coolan t and raise the temp? Says when the temp goes high, he can smell antifreez e, probably blowing out the overflow.

+1

I can't explain the behavior of why it runs hot at idle in terms of the leaking headgasket. I'd suspect that there might be another problem, like blocked radiator, that's the real problem, even though OP says that has been ruled out. If there is a separate cooling system problem, that could have allowed the car to overheat, warp the head, and that's why the head gasket is leaking. Symptom of partially blocked radiator can be overheating at idle. With the car not moving, less air moves through radiator, so it needs more radiator performance that when it's moving.

[Tony Hwang]

Hi, Today's new cars rad. fan is thermostat controlled electric motor driven. So Air passing thru the rad. is not like old cars. If suspected we can do the rad pressure test with dye which will tell what's going on. If it is a leaking gasket problem the sooner the repair is done the better. Or bigger problems will happen.

[bob haller]

te:

he engine runs rough all the time. Watch does with it is not my concern.

apidly. If he puts in neutral and revs the engine, he says it drops to nor mal quickly. Radiator, fan clutch, thermostat, water pump all checked out and working normally.

lant pressure drops, which could be letting more exhaust leak into the cool ant and raise the temp? Says when the temp goes high, he can smell antifre eze, probably blowing out the overflow.

all garage needs to do to check for exhaust leak into coolant.

removed radiator cap run engine with cap off, check for carbon monoxide at caps location.

also try pressurizing cooling system with pressure tester.

if pressure goes down their is a leak somewhere.

[clare]

Answer to the first question will answer the second one.

[Ashton Crusher]

What he should do is go buy some "block seal" in a can and follow the instructions exactly. That stuff sometimes actually works. The worst that can happen is you are out the $30 for the stuff. At this point he has nothing to lose but the $30.

[bob haller]

ngine runs rough all the time. Watch does with it is not my concern.

ly. If he puts in neutral and revs the engine, he says it drops to normal quickly. Radiator, fan clutch, thermostat, water pump all checked out and working normally.

pressure drops, which could be letting more exhaust leak into the coolant and raise the temp? Says when the temp goes high, he can smell antifreeze, probably blowing out the overflow.

but it will clog the heater.........

[clare]

I wouldn't say it WILL clog the heater. There is a chance it will plug the heater. For the uber-cautious, it's generally not hard to bypass the heater core and even the heater valve untill the leak is sealed.

[bob haller]

e engine runs rough all the time. Watch does with it is not my concern.

pidly. If he puts in neutral and revs the engine, he says it drops to norm al quickly. Radiator, fan clutch, thermostat, water pump all checked out a nd working normally.

ant pressure drops, which could be letting more exhaust leak into the coola nt and raise the temp? Says when the temp goes high, he can smell antifree ze, probably blowing out the overflow.

it clogged my heater core, the dashboard had to be taken apart to replace t he heater core. it was a dodge caravan.

i learned a costly lesson........

[Tony Hwang]

Hmm, Same happened to me on Ford PU truck in winter time. It can go both ways. Solve the problem at least for the time being or else.

[Snuffy "Hub Cap" McKinney]

the engine runs rough all the time. Watch does with it is not my concern.

rapidly. If he puts in neutral and revs the engine, he says it drops to normal quickly. Radiator, fan clutch, thermostat, water pump all checked out and working normally.

coolant pressure drops, which could be letting more exhaust leak into the coolant and raise the temp? Says when the temp goes high, he can smell antifreeze, probably blowing out the overflow.

Thanks guys. How long would you expect it to take to know if block seal works?

Engine & heads are cast iron.

[Ed Pawlowski]

Takes only a few minutes to a half hour. Plugging the heater core can take an hour or so.

Best way to handle it is to warm the engine, add the block seal, teh let it run while you look at the ads for new cars because yours may be junk with a bad head gasket and plugged heater core. No way I'd trust that crap. But... it is your car so do as you please.

[trader_4]

te:

he engine runs rough all the time. Watch does with it is not my concern.

apidly. If he puts in neutral and revs the engine, he says it drops to nor mal quickly. Radiator, fan clutch, thermostat, water pump all checked out and working normally.

lant pressure drops, which could be letting more exhaust leak into the cool ant and raise the temp? Says when the temp goes high, he can smell antifre eze, probably blowing out the overflow.

That's a good point. If it's a car made in the last couple of decades, it probably has an electric radiator fan. If that isn't running when the car needs it, ie when the temp is going up, that would cause overheating. Even many older cars had auxiliary electric fans to supplement the mechanical, belt drive one.

[Snuffy "Hub Cap" McKinney]

engine runs rough all the time. Watch does with it is not my concern.

rapidly. If he puts in neutral and revs the engine, he says it drops to normal quickly. Radiator, fan clutch, thermostat, water pump all checked out and working normally.

coolant pressure drops, which could be letting more exhaust leak into the coolant and raise the temp? Says when the temp goes high, he can smell antifreeze, probably blowing out the overflow.

- most head gasket leaks crate white exhaust.

-

- if coolant leaks into oil engine will soon be siezed

Milky coolant from engine, but no water in oil.

[Snuffy "Hub Cap" McKinney]

Any other risks you folks know of? Clare's idea of bypassing the heater & valve would take that out of the loop. Will pass that on to the neighbor and let him decide. Pretty mild weather here - won't need a car heater for at least 6 months.

How does block seal work? If it doesn't seal and then he gets the head done, would the seal residue be a problem?

Any recommended brands? Searching I see K&W, Bar, CRC.