Smell gas in coolant, no water in oil. 97 Expo 5.4

[nealcox17]

Hello, this is my first post, I really like reading all of the different posts on all makes and models. yesterday, i started to smell a gas smell in my coolant reservoir. Saturday i replaced my radiator, water pump, thermostate. I went out of state and it droove well but when i started the next morning, alot of vapor smoke and started hard, missing then leveled out. Please tell me one of my heads is not cracked. this Expo has 249,000 miles and i really hate to junk it. Is it possible the intake manifold gasket is bad? There is no water in my oil at all. Would really help if someone has some ideas......Neal

 

[toms89]

What your describing sounds like a leaky head gasket. Could be cracked head/block but less likely.

You could do a leakdown test to confirm or take it to a shop and have them test for exhaust gases in the coolant reservoir.

 

[stamp11127]

Gas smell in the coolant isn't a good sign, can come from a few areas, none of which are easy fixes. Usually a blown head gasket or cracked head. Your at the point of running some basic tests to find out what the problem is. Are there bubbles in the coolant when running or evidence of higher than normal coolant pressure when removing the radiator cap?

 

[nealcox17]

ive noticed the radiator cap hissing when i loosen after its cooled. the smell is strong. ive checked my oil and see no signs of coolant/water in my oil. i replaced the radiator and water pump and thrmostat, i never smelled the gas before, but its very strong in the overflow. Im a small engine mechanic so im mechanically inclined, just wondering if i should invest the time and money to repair. I appreciate the responses.

 

[stamp11127]

You should have noticed the ordor when changing the water pump and radiator. You will get a slight hiss when popping the cap on the tank.

Before tearing into the motor I'd flush the system and surge tank, mix a new batch of coolant and see if the smell returns. If it does then perform a leakdown test or pull the plugs and inspect. Might get lucky and it shows on a plug.

Follow "Banker with tools...." in the How To Section for his ongoing journey into head repair.

 

[nealcox17]

with 249,000 miles, do you think a repair is good judgement?

 

[stamp11127]

Depends on your finances, condition of vehicle etc. Judgement call for each owner. On paper it usually isn't worth the investment. I just have a problem with paying upwards of $20,000+ for a newer truck that will give me the same crap a few years down the road.

 

[Jeff532003]

with 249,000 miles, do you think a repair is good judgement?

I think with that many miles you might want to consider an engine swap. I'm sure you can find one at a salvage yard in the 100k range for a reasonable price. If the truck is otherwise pristine you could consider doing a long block as well. All depends how long you can afford to be without a vehicle. 249k is very high miles. If its still the original tranny I'd expect trouble from it at some point as well. All the maintance in the world can't preserve the clutch packs forever. They wear out.
I will say this. Any head issue I've encountered where exhaust is leaking into the coolant the vehicle runs hot and often boils the coolant. As stated above you can pull your plugs and see if and which cylinder leaking as the plug will be nice and clean thanks the the steam cleaning your coolant is giving it. If all your plugs are sparkling clean then it's a manifold leak most likely.

 

[nealcox17]

thanks for the input guys. I havent decided if im going to tackle it myself or not, but knowing the miles, i probably wont pay someone else and too, the tranny is liable to go out anytime in the future. i really like the suv and for now am running it with radiator cap loose, the heat is hell to get going but isnt overheating at all in the short distances i drive, no more than 5 miles. i want to get another one, different color, maybe blue or maroon or black and build it somewhat, new rims, lift, etc... My 1997 has been by far the best vehicle ive ever had. Very thankful. We have 6 kids, 18 and under and it helps to have the 8 passenger seating that it does. An Excursion is also a possibility, but i know that an Expedition can be a great vehicle. Can a tranny rebuild kit be purchased?

 

[stamp11127]

Yep, google for them and the books are available also. The trans of today aren't like the ol TH350 or TH400's. More electronics and more sensitive to contaminated fluid. Cleanliness is very important now.