Blown Head gasket???

[Nice140Y]

Hi,

I have a suspicion of a blown head gasket. on my 69 510. How can I verify this?

I see a bit of whit smoke on cold starts only. It lasts for about one minute and goes away.

It is very cold where I live so I thought maybe just condensation.

I was told to check the plugs. Idid and found that the back and front plugs are a bit black and the two middle ones are very light.

I will post photos tomorrow.

How else can you tell if the head gasket is blown?

 

thanks.

[Skib]

is your oil milky?

[Nice140Y]

As far as I can tell, no. It is vary clean and golden. I only have 1K miles on it though.

[elmerfudpucker]

I was told to check the plugs. Idid and found that the back and front plugs are a bit black and the two middle ones are very light.

 

Light brownish grey or clean? If clean, then water got in there. Also check the distributor and the rotor button, moisture +or corosion in there would do the same thing.

[LAYEDOUTB2K]

White smoke on start up is very common on any vehicle if it is really cold out.

 

A few other signs of blown head gasket:

 

sweet smelling exhaust (coolant burning)

bad smelling and foamy coolant in radiator

coolant bubbling in radiator(pull radiator cap, start car and look in the radiator)

check compression (hot and cold)

[datzenmike]

White start up exhaust is totally normal at this time of year, all cars do it. Water dripping from the pipe is just condensation.

 

1/ Unexplained coolant loss would be a concern.

 

2/ If you notice shortly after starting that the rad hoses look swollen and the rad spits coolant out the overflow hose, that would be a concern.

 

3/ If after starting you notice bubbles working their way up and out the open rad cap, that would be a concern.

 

 

 

Constant coolant loss could just be over pressurization after shut down of a hot motor. The rad cap vents it into the overflow pipe. (on older vehicles it is dumped on the ground) Installing a coolant recovery container and a special rad cap will allow the rad coolant to be stored and when the rad cools the special cap allows it to siphon back in. Very efficient and foolproof. An ordinary rad cap won't work for this.

Edited December 17, 2009 by datzenmike

[Dudeman]

Based on what you said it doesn't sound like you have a blown head gasket. You would eventually (most of the time quite quickly) loose all of your coolant and the motor would overheat and die, and your oil would clearly be milky and frothy from the coolant. Most all vehicles smoke on startup when its cold, my 620 does quite a bit. If your plugs are black and sooty you could have carb problems, but I think you would know for sure if your head gasket blew. When I blew mine I barely made it the mile and a half home, and even after that little bit of driving my exhaust was badly warped. If it runs consistently ok I bet your fine, if you are really worried you can replace the gasket anyway.

[dat521gatherer]

not always will there be water in the oil. my blown gasket had oil in my radiator, but no water in my oil. i drove it like that for more than a year. the piston rings were gone ant a skirt in the bottom of the pan.

 

look for water or oil leaks on the left/starter side between the head and block

compression test

leak down test

[I'm BLUE]

I am just going to echo my experiences with what other memebers have already expressed

 

(1) As DatzenMike said cooling systems can be over pressurized ! check for swollen hoses / loss of coolant / keep an eye on coolant level/color NOTE: 1991 Ford F-150 pressurized cooling system so much it finished off the core plugs ( freeze plugs.

(2) As Squib said " is your oil milky ? " you said no ( I have had this happen 2 times )

(3) Dat521gatherer is correct ! look for external FRESH oil or water leaks ( water leaks can be very hard to find on new cars , but should be easy on datsun's )

(4) It is possible for head gaskets to leak oil/water into the next cylinder and run fine after warm up ( owned a subaru that did this, but rare situation , re-did the head-gasket and walla !!! )

(5) Typically I see Head Gaskets blow between the cylinders , and can do anything they want.

(6) Like dat521gatherer said "look for water or oil leaks on the left/starter side between the head and block

compression test and perform a leak down test "

(7) around oregon you can by test kits that drop into the coolant , and verified by the type of color that it will display afterwards ( think pregnancy test ) , but again it can be blown where there is no coolant passages ! ( I.E between cylinders.)

(8) If you decide to take the head off , check for any discoloration in the head gasket as well ! ( sometimes you get lucky and it shows up , sometimes not ! )

 

 

(6) can tell you very quickly , go to sears ( or just pickup a compression test gauge set for engines ) , pickup craftsman compression gauge checker set , pull out plugs one at a time , insert tool quick , crank over a few times , record the readings , ( make sure ignition system is disable like taking out the rotor or take off the cap.) Record all compression check numbers , and look up specs in the haynes manual or google. Next perform a leak down test too ! Remember you can also have a warped valve or cracked valve seat ( not common , but common enough if you know what I mean ! ) If it was a burnt valve it would be a dead or almost dead cylinder and would be very noticeable all of the time ( run like crap ! )

 

NOTE: It is a good idea to spend the extra money to have the head magnafluxed/pressure checked if need be if you decide to perform a head gasket job ! Don't use "fix it" in can type products , cheaper to buy and do yourself if you have the tools ! It will also be done right !

 

Hope that helps a bit !