Is Head Gasket? Or Intake Manifold Gasket?

Hey guys.
I got a Windstar at last Thanksgiving for 500 bucks. The seller said it has blown head gasket so getting rid of it. With 133k miles.

When I drove it home, the car shakes due to misfire (with CEL, cyl 6 misfire). So initially I thought it's a symptom/consequence of blown head gasket.
Recently when I started to work on it, I found the spark plug on cyl 6 has crack on ceramic. After changed it, the engine runs pretty nice, no more misfire.

For the gasket issue, the typical symptoms of bad head gasket are:
1, there is oil residue in coolant resevoir.
2, white smoke from tailpipe.
But the following situation is not match with bad head gasket or significant bad head gasket:
1, It runs fairly good, even will be near perfect if replace all the spark plugs and spark plug wires.
2, no overheat (maybe cuz I removed the thermostat to flush and apply blockseal??)
3, the coolant (tap water mixed with blockseal acturally) does not surge or heavily bubble when engine is running. I used block seal (both bars leak and k&w), but it seems doent work, sometime good sometime not (based on the white smoke intensity). No strong exhaust smell from coolant.
4, oil looks okay

I did a lot of research, and found intake manifold gasket is a common and possible problem on 1999 windstar 3.8L. I hope so, much better than replace head gasket. So based on these clues above, any suggestion?:uhoh:
Thanks guys

First thing i would do is a compression test that will tell you if the head gaskets are gone or a radiator pressure test will do the same if it doesn't hold pressure the water is going somewhere whereas the compression test will show low compression which is one sign of the leaking head gasket.

If the van doesn't overheat i would say it's not a head gasket but you can start by changing all the plugs and take it for a short drive and if it starts getting hot it's time to do the head gaskets but don't let it get too hot for too long or you can warp the heads.

but personally if it was mine and i paid 500.00 for it and it seems to run fine i would drive it and hope for the best..

Get a loaner pressure tester at Auto Zone or advanced pump up to appx.14psi with the motor running usually they will pulsate if a head gasket is bad.

Thanks guys.

After removed thermostat and filled with blockseal+tapwater mixture in the cooling system, I have had it idle for pretty long time (up to half day), and also short distance drive (~10 miles). BUT NEVER OVERHEAT. The temprature gauge rise steady and reach the normal operating temp finally. I am not sure if it means not head gasket, or simply because I removed thermostat?:uhoh: Any idea?

I have a 02 Nissan sentra 1.8L used to be head gasket leaking, the first symptom is overheat (CEL and can be seen on gauge), and no heating (heater core blocked by air pocket caused by combustion gas leaking). It leaks maybe not serious, no visible pulse in coolant but some bubbles. And with some really weird smell from coolant resevoir (guess it's combustion gas smell).

Mustang, if it doen't overheat after quite long time idle (up to 3 hours) and some drive (10 miles) (without thermostat), and it runs not bad, can I almost eliminate the possibility of blown head gasket?

i would put the thermostat back in top up with antifreeze and drive it just keep an eye on the water level and keep a jug of water in the van keep it to short trips. for now after a little while just keep checking the water level and oil to make sure it's not getting water in it and if say after 2 fuel fills things look ok i would drive it. i always keep a 5qt jug of oil and a jug of premix antifreeze in mine because it really sucks being stranded in the middle of nowhere. Well if you get 3 months out of it you got your 500.00 out of it. i paid 3000 for mine and had to fix the 171&174 & p0401 error codes 2 weeks after i signed the paperwork might put mine up for sale and buy a smaller car but i am happy with it at the moment

I have run out about 1/4~1/3 tank of fuel most on idle running and a little driving. It indeed does not overheating. White smoke comes out intermittently. Sometime looks bad, sometime seems like totally healed, but maybe next morning it has white smoke again. I don't drive it normally, only test it for a little while in these days.
I have put it in my garage, will start the project once determine the direction (lower intake gasket, or head gasket). It will be the first big project for me >_<

Okay i didn't understand the white smoke coming out the exhaust is a clear indication of head gasket (Greyish-white) which means a big job hope all goes well

Don't over-react to the normal steam that comes out in the cold morning start-up.
Are you needing to add coolant to the system?....if not, you are fine.
If you do need to add coolant there are 2 things more likely than a head gasket.
Head gasket failure is rare on a post 1995 windstar, though the lower intake manifold gasket will give many of the same symptoms......if the gasket is leaking coolant into the intake.......it is going to go into the cylinder.....
One is the lower intake manifold gasket that you mention.
The other is the front cover gasket that seals the cover on the front of the engine (passenger side end) that the water pump is mounted on.
Of course, you want to eliminate the easier items like a loose hose clamp and other leaks.
If you do the lower intake manifold gaskets, put a new bypass pipe on....the one that goes from the water pump, through the lower manifold, over to the driver's side and has a heater hose connected to it.
The metal part of the bypass tube is known to break down.

Also.....I would replace the isolator bolts that hold the upper intake manifold to the lower manifold as the bushings on those bolts break down from exposure to oil.
This....and other helpful guidance is available in this link.
http://leckemby.net/windstar/windstar01.html

A 1999 will have the issue with the hole in the baffle in the front valve cover under the PCV valve.

You will want to clean out the EGR ports in the lower intake manifold also.
Use care to avoid fluids and junk getting down the intake passages in the head......to the valves.
The lower intake manifold gaskets are to be DRY FITTED, no sealant other than a small dap at the ends where they meet the end seals.

If the front cover is leaking, that is a major job due to access.

Both of these jobs, if done correctly, are a one time repair.
The new gaskets have been greatly improved to correct the reason the originals failed in the first place.

On my 1996, Stop Leak (the original pelleted type) solved my very slightly leaking front cover gasket.
However various sealants did not completely correct the lower intake manifold gasket issue.

Before removing the fuel injectors from the lower intake manifold, clean/flush away all the dirt you can from around the fuel injector. Those are 6 dirt traps and you don't want that grit falling down into the hole when you pull the fuel injector up.

Of course, an oil & filter change must be done after you do the lower intake manifold gasket job BEFORE starting the engine.

Wiswind, you are awesome! Very helpful information.
UPDATE: I have opened the engine, until the lower intake gasket. I think I got the root. Initially I found there is thick milky oil residue (almost same with blown gasket oil color, cappucino or peanut butter like) on the 4 of 6 long bolts which fix the lower intake gasket. And there is also leak evidence on the gasket, both upper and lower, can not seal the water and oil very well. I have ordered part on ebay, it's on the way. I cleaned the intake manifold with 2 bottles of throttle body cleaner. A lot of fouling in it, due to its age, probably also the oil/water mixing.
I found the stop leak stuff doesn't work on lower intake gasket, due to plastic/rubber surface and exposure to oil. I can see some micro metallic scales that formed from block seal, but not attached the surface at all.
By EGR ports, is it the little holes in the intake manifold? Can I just flush them with throttle body cleaner?

Many thanks

You have gotten some good advice that I don't think you have yet followed. Using the radiator test gauge while idling will indicate if there are pulses from the combustion chambers. Also the cylinder compression test is good ... but not as good for showing small head gasket leaks ... but it is great for indicating wear and tear on engine.

The engine not overheating tells you little about the head gaskets.

This (3.8) engine has some notorious leaking spots other than the head gaskets ... the front engine cover gaskets and the lower-intake manifold gaskets. I am just now repairing both on my '99 ... hope to have it running again in a couple of days. I removed the sub-frame supporting bolts and supported the sub-frame on a couple of wooden rails. Then I pushed the engine over and blocked in place so I could remove the front engine cover with engine "in-place". Both of these gaskets have coolant passages in them ... and the gaskets just get old and fail over time (kinda like I'm doing!). I am adding Permatex #2 around the coolant passages on the front cover gaskets ... and adding Permatex Grey RTV around the passages on the lower intake gaskets. Time will tell if it does any good.

Oops ... I was typing while you were typing.

I found what I thought were leaks in both the front engine cover gaskets and the lower intake manifold gasket.
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I cleaned the EGR ports with common wood decking screws followed by brake cleaner. I find gasoline/diesel fuel and Scotch-Brite (elbow grease) necessary to clean the head and lower manifold surfaces ... they need to be shiny clean again for good purchase by the sealant and gaskets. Be sure to protect the crank case and combustion chambers from falling debris.... by laying sheets over the open crank case and plugging all holes. I use a couple of rolls of blue shop towels for this job .... and several cans of brake cleaner.

Cuz I feel the rear 3 spark pluga are really hard to access. Based on some interpretation and assumption, I decided just open the intake manifold to take a look.
Btw, your idea is worthy to take a try, I mean put some Permatex gray around coolant passage.
For front engine gasket, will it cause oil residue in water, but no obvious water in oil (eg milky color oil on the dipstick).

Yes, they both will cause the same oil-to-coolant-to-oil crossover. If you have enough coolant in the oil to "see" ...anywhere... you've got a lot of crossover. Its best, even when you think there is no leakage/crossover, to have a test done by a lab ... such as Blackstone.
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Its a shame the coolant passages are designed such as they are in this engine. its a result of designer laziness ... the intake manifold does not need coolant ... most in-line engines will be found with "dry" intake manifold ... no coolant. In Vee engines, its just so easy for the designers to pass the coolant through the intake manifold ... or the front engine cover (if there is one) ... but more advanced engines have "hose-a-rounds ".. or even relocated coolant pumps.

I will keep looking after receive and install the intake gasket. I never open an engine before. It's my first big project. Hope I can put every thing back correctly, and it still running. Crossfingers.:uhoh:

Don't go faster than you can clean and protect.

I just follow ford workshop manual step by step, and get back to youtube when I got stuck:)

BTW, Bellingham is where we often overnight when we are picking up folks flying in to Vancouver. That whole section of the coast is very nice.

Thanks. That's also why my family settled here from NYC. Totally differnt feeling from big cities, both landscape and society.
The best time in the year is coming soon.

BTW, Bellingham is where we often overnight when we are picking up folks flying in to Vancouver. That whole section of the coast is very nice.
UPDATE:

I replaced upper and lower intake manifold gasket. Thanks GOD, after I put everything back, it still runs! Bad thing: the white smoke still there.
So I bought a compression tester. I was fear of that before, cuz the back side spark plug holes are really really tricky.
So far, I have tested front 3 cylinders, all are 165-170 psi. Seems good. And I also pulled back spark plugs. Didn't test back 3 cylinders, cuz it's much more difficult than pull the spark plugs.

THERE IS ONE THING SUSPECIOUS: There is alot of oil sludge on the outside of the front side engine (pretty thick), but back side is fine. Is is also an indicator of leak head gasket(not necessarily blown, cuz the cylinder pressure seems okay)?

Thanks guys

UPDATE:

I replaced upper and lower intake manifold gasket. Thanks GOD, after I put everything back, it still runs! Bad thing: the white smoke still there.
So I bought a compression tester. I was fear of that before, cuz the back side spark plug holes are really really tricky.
So far, I have tested front 3 cylinders, all are 165-170 psi. Seems good. And I also pulled back spark plugs. Didn't test back 3 cylinders, cuz it's much more difficult than pull the spark plugs.

THERE IS ONE THING SUSPECIOUS: There is alot of oil sludge on the outside of the front side engine (pretty thick), but back side is fine. Is is also an indicator of leak head gasket(not necessarily blown, cuz the cylinder pressure seems okay)?

Thanks guys
They make two type of compression testers. Use the hose and tighten in by hand the rubber o-ring usually seals Then put the gage on and check the compression. You could use the other type and hold on plug hole and check the compression.
Napa sells a kit that checks for combustion in the anti freeze. You can also get a pressure tester pump up to appx. 14 psi and run engine if gage pulsates you have a blown head gasket.

Don't expect it to run well when you first give it a try after extensive service ... I've been at it a number of years and I always knock something loose .. vacuum hose, spark cable, sensor connector, injector connector ....something that will make me feel really foolish when it finally uncovers itself and I refasten it... hoping no one is watching too closely! LOL!

BTW, if you are trying to service the engine without removing the wiper arms and the "cowling" .... well, shame on you! Removing the cowling is covered in the body section of a Haynes ... not much too it. And it makes servicing the back side of the engine much simpler.

As I have written, doing a cylinder compression test is good maintenance ... but is not very conclusive about whether a head gasket is blown or not. I much prefer the coolant pressure test.
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I really doubt if a head gasket is blown ... this short block on the 3.8 is really robust.

Oil smudges could well be from a leaking valve cover gasket.
The front one is quite easy to replace.
The rear one is more difficult do to access, even with the wiper cowl off.
It is very unlikely that the oil leakage is from a head gasket issue.

Monitor the coolant levels.
NOTE: it is normal to need to add some coolant as the system 'burps' out the air pockets in the system.
However, you should have NO coolant leakage, and the bubbles should clear out quickly.
Also, remember that you will have steam from the exhaust when you first start up the engine, particularly in cold weather.
I hope that you changed the engine oil & filter before starting the engine up.
If you did not, I would do so.....and don't run the engine any more until you have new oil and filter.