Howdy,

My 02 SCrew (4.6L, 170k miles) went into limp mode recently.

We took it to the local Ford dealer and they said it was a head or head gasket. Big $$.

I wanted a second opinion so I took it to a local mechanic who used to work as service manager at another Ford dealership. He said that it was the thermostat and replaced it.

I've had the truck back for a couple of weeks and went into limp mode again.

I checked the codes and had O2 sensor, misfire in #1, engine overtemp codes.

The O2 sensor is a computer issue and can't be easily fixed, it has been that way for a long time. The misfire in #1 has been fixed by installing a new spark plug.

The engine took about 1.8 gallons of water to fill the tank so I'm guessing that the problem is a head or head gasket since there are no observable leaks and we've driven approximately 200 miles since getting it back.

I tried to pressure test the coolant system but the tester at the parts store doesn't fit the threaded cap on the tank.

I have noticed no smoke or odor from the exhaust.

What advice can you offer?

Does anyone have experience with Blue Devil gasket sealer?
http://www.usasealants.com/products/...asket-sealant/

Thanks,

 

Get a head gasket leak tester. About $50 at the local autoparts store. The tester goes above the radiator cap with the engine running and "sniffs" for hydrocarbons in the coolant. If the blue liquid turns yellow, you have a bad head gasket. Im surprised the other shops have not done it. Your #1 spark plug probably went bad because its getting damaged by the coolant it is burning.

Unless you have coolant in the oil or vice versa there isnt other way to tell if your head gasket is bad, perhaps maybe a leak down test.

 

The head gasket sealer does work in many cases and would be a good place to start, but be sure to cut off your heat or it might clog your heating coils. Check out Thermagasket and Steel Seal also. That is what I would do if I was in your situation. If it works for you (it works in about 90% of the fixes) it could still be working when you decide to sell your truck many miles from now. The concept is simple, under heat and pressure the chemicals in the sealant clog up and fill in the tear in the head gasket and then harden to become gasket material. It's the same concept as clotting blood stopping bleeding. Blood doesn't normally clog up your arteries but when air hits it in a wound, it turns to a hard material. and seals what is basically a pressure leak.

 

I'm 99.9% sure that it is head gasket.

The exhaust is very moist and my wife says that she has noticed a sweet odor from the exhaust.

I agree about the previous shops. Now that I know how easy it is to check, I cant believe neither of the shops has the equipment at the ready to prove or disprove the problem.

Pickupsrule, thanks for the info. 90% success is a pretty good rate.

I'll let you know the results.

 

Ive used Steel Seal before (worked for a cheap *** used car dealer). It did work most of the time, but I cant garuntee longevity. And its about $90 for a V8. But cheaper than a $1500 head job.

 

Only problem with head gasket sealers is if its leaking into the oil. If the product comes in contact with the oil you can pretty much scrap the engine. I have seen it too many times..

 

There was no evidence of coolant getting into the oil.

I put it in the motor tonight we'll find out soon enough if it works.

 

x2

It is your head gasket....It sounds like you are doing this...

"I know what the problem is, but maybe if I do more digging I can change what the problem is."



It has already been said, but I will say it again, because it sounds like you need it. (Btw, it is hard to tell my tone of voice through text, but this is said with a non-attitude-ish smile on my face)

Truck goes into limp mode either because there is low oil,or low coolant(in this case, probably coolant). The ford ECM is smart and cuts it off before it can overheat.

Cylinder #1 goes out because of corrosion on spark plug because of the coolant that is being put into the cylinder.

The reason why your shadetree mechanic fixed the problem(temporarily), is because the engine was out of coolant, and when he replaced the thermostat, he had to put more coolant in.



It is up to you if you want to take a $4000 dollar risk(new engine) by putting in blue devil and HOPING enough coolant is not getting into the oil to ruin the engine. Because you don't need MUCH blue devil to ruin it.

Shops do not use blue devil, because blue devil is a HIGHLY temporary fix. It's like putting a bandaid on a gash....Hm, that is LITTERALLY what it is.

PS. I apologize for using so many CAPITALS...

 

To give you a idea. Temporary head gasket repairs are just that. It will only take about 1 oz of the the 8oz bottle to get into the oil to completely destroy the engine. The first thing that goes is the oil pump, then the camshafts seize. After that the cranks shears the keyway in the crank, and piston slap some valves..

I have a BHG in my 97 and she is sitting until i get the next engine ready to go back in.

 

Thanks for your concern. I do appreciate it.

However, I was already looking at replacing the entire engine. My mechanic from "back home" (I moved recently) who I trust implicitly, said that replacing the whole engine with a running, low-mileage replacement was the most cost effective choice when compared to replacing the head gasket because of the labor costs involved in tearing the engine down. He thought I may have a cracked head anyway. It has been hot enough to go into limp mode 3 times now (my bad).

With that said, I felt I had little to lose.

I replaced the thermostat tonight and I am happy to report that it seems to be working for now (no sputter at start-up as it had been doing). I understand that this is a temporary fix.