Head gasket question?

rafo802

Hi,

When looking to buy a second hand car, what are the warning signs a buyer should look for showing the head gasket is clearly gone? Is there any clear indication which singles out this problem?

All info appreciated.

Regards.

Anan1

rafo802 wrote: »

Hi,

When looking to buy a second hand car, what are the warning signs a buyer should look for showing the head gasket is clearly gone? Is there any clear indication which singles out this problem?

All info appreciated.

Regards.

The only way to be sure is to do a compression test, but whitish mayonnaise-type deposits on the inside of the oil filler cap are a warning sign, as is white vapour from the exhaust. You could also remove the rad cap to see if the coolant is bubbling when the engine is revved, but be very careful. There are kits to detect CO in the coolant, but I don't know how much they cost. Is this about a particular car, or just a general question? If the former, do you have reason to think the HG's gone?

king_of_inismac

Everything above is correct.

If the HG is gone, the car will overheat. You'll either have water in the oil (mayonaise in oil cap) or oil in the water (dirty coolant resevoir).

However both of these can be cleaned/removed for a test drive. White smoke from the exhaust is a sign sure, but nothing definite.

If you're in any way unsure, walk away!!!!!!!

rafo802

Hi,

Thanks that helps, so what you are both saying is i should,

1. Check the inside of the oil filler cap for white residue.

2. Check for white smoke from the exhaust...would this be clear when the engine is just running? or would i need to rev the engine a few times?

3. Check if the coolant is bubbling...but would the engine need to running for a few minutes to prove this?

I suppose it's just a general question as i'm looking to buy a secondhand car at the moment. My experience with cars + head gaskets in the past has proved to be the most expensive of all repairs, so i would just like to completely avoid this.

Would lots of black oil staining around the top and underside of the engine be any proof of a head gasket problem or is this a completely differerent problem or even a problem ar all?

Regards.

best thing to do is to get a mechanic or a competent friend to have a look, messing about with expansion tanks when you are not sure what you are at is not a good idea to be honest. Also in this weather spotting water in exhaust fumes is a guess unless the hg is like a sieve

Yawns

on the topic of head gasket I got a car a few weeks ago, it looked like it had a head gasket prob but I got the car for free, so I said I'd stick into the NCT first to see what else was wrong. There was yellowish-white mixture underneath the oil cap, less than minimum coolant and basically no air intake hose.

I did a quick oil change, no filter, to see if I could flush it out. Used engine flush and a thicker mix of oil. Wiped gunk off. After a few mins driving noticed the gunk was coming back still.

Before the test I replaced the air intake hose as I knew that the nct fella might open bonnet, see it in half and just say fail. I spent 4.70 on this, threw it in the nct and it failed on drivers nearside tyre only. Went home changed tyre and it passed. Checked the oil cap as I did about 35 miles total driving to and from nct site altogether. No gunk on cap only some black oil. I had also topped up coolant before the nct too.

So could it simply have been no air being fed into the engine that could have caused this gunk?

There is only 115k miles on it. 1997 car. Brakes and tyres are fine and it looks like the gunk is gone since I attached the new hose. Anyone ever encountered this before?

As I paid nothing for it, the car only stands me the cost of the NCT, €50 and it now has almost 2 years left. 3 Jan 2012 is next due.

Almost convinced to keep it and just give it a good servicing. Oil change again but with proper brand oil, oil filter, air filter, sparks. Don't need brake pads as they seem in very good cond. The cam belt was done at 91k miles so just over 20k miles ago. How often would a cam belt be changed?

mondeo

White stuff under the oil filler cap is not a 100% reliable way of identifying a hg issue, I've had cars with blown hg's and I never saw any white under the oil cap.

If it's a slow leaking hg the car could drive normaly for up to 45 minutes before over heating. I have had this particular one too which would be non detectible in your 15 minute test drive unless you have a test kit to detect gas's in the coolant.

Some white coloured smoke from the exhaust when cold is normal, but when the engine is hot it would be a tell tale sign of a hg issue. When the engine is up to normal temp floor the accelerator and look out the back window for blue or white smoke which would be a bad sign.

BrianD3

White/cream gunk under the oil filler cap often means that the car has had a lot of short journeys and the engine has not had a chance to warm up properly.

If there is creamy brown gunk on the dipstick that might be a sign of a blown head gasket.

Mr Benevolent

Would lots of black oil staining around the top and underside of the engine be any proof of a head gasket problem or is this a completely differerent problem or even a problem ar all?

That's evidence of a massive oil leak.

Tea drinker

Indeed a car which has been lying up or is only took on short journey would have crap on the cap, it's just water condensed from the air in the engine. A good long drive gets it out.
If there is oil around the headgasket it might mean it's gone. Not to be confused with a leaking Valve cover gasket, which is a cheap and cheerful fix.

AgileMyth

rafo802 wrote: »

what are the warning signs a buyer should look for showing the head gasket is clearly gone?

A Fiat badge on the front is usually a dead giveaway:D

Run_to_da_hills

AgileMyth wrote: »

A Fiat badge on the front is usually a dead giveaway:D

Fiats and blown head gaskets go like custard and cream. :pac:

johndaman66

mondeo wrote: »

White stuff under the oil filler cap is not a 100% reliable way of identifying a hg issue, I've had cars with blown hg's and I never saw any white under the oil cap.

Would have to agree with the above. Had a blown headgasket once and there was absolutely no sludge under the oil filler cap. The oil and water were not mixing as such or at least not to a great degree but the water was being blown out the exhaust. In the end it was quite bad, taking up to a jug of water for a 70 mile round commute. In this instance I had plenty of warm air inside the cabin of the car but another time a headgasket went on me in a different car I was getting little or no warm air in the cabin of the car....another warning sign for you OP.

stevenmu

Yawns wrote: »

So could it simply have been no air being fed into the engine that could have caused this gunk?

Yes. As mentioned, the white cream/gunk is caused by moisture in the oil. A blown HG is one way that the oil can collect moisture (from coolant leaking in), but oil will tend to pick up a small amount of moisture anyway. During longer drives the oil will get hot enough to burn off the moisture (shorter drives won't which is why a car with a lot of short trips may also have gunk), and often the air intake will have a small feed to the oil reservoir to let air through and help with this (I think it also helps regulate pressure?). So with the air intake disconnected the oil would be burning off less moisture, especially with the shorter trips you mentioned.

Gary ITR

@Yawns
My car has an air feed from the rocker cover to allow it cool, when it was initially modified it was blocked and caused all sorts of blue smoke. No air feed could cause all sorts of unforeseen problems tbh.

But the long drive could also have helped with cooling. It's not uncommon for a car with a blown head to run fine on a motorway then as soon as it hits traffic it gives up the ghost

Yawns

Yeah I think the previous owner was just a short trip woman

I myself live in the country so it will be longer trips anyway even if it's just to do the weekly shop. Well I'm gonna consider having the tax renewed and getting it insured. At least it has the nct for 2 years now and if I keep it, it'll be looked after well.

Does any insurance company do multi-car policies? I'm assuming not but would love it if one of them did It can be done in England I know only a shame the insurance companies here say it's not done anywhere in the world. ( Axa told me this, I told the woman has she ever seen the admiral ad at least on sky...oh yeah... )