mhh263
New Member
- Joined
- March 29, 2010
- Messages
- 5
- Reaction score
- 0
- City, State
- Chesapeake, VA
- Year, Model & Trim Level
- '94 XLT
I bought my 94 Explore over a year ago and it was running great for 9 months. But the last 3 months the truck was progressively running rougher and diminishing gas mileage. Then I started getting concerned because I was losing coolant. But my number one concern is my left side of the engine was running very hot as evident of spark plug for cylinder number 4 which after two week looked like it’s been in there for years; very burned. Prior to that, it got so hot that plug 4 shattered. Also DFPI and IAC valve had physical burn marks. Although the old head gaskets revealed no cracks or breaks, I did notice the previous owner did not properly clean the surfaces. I also had the sneaking suspicion he re-used the old head bolts instead of new bolts. The lower intake manifold gasket looked suspicious however.
Fearing I had a cracked block, I took them to a machine shop that specializes in engine rebuilds. Surprisingly there were no cracks. The guy at the machine shop said they were the dirtiest heads he has seen in years. Possible clogged coolant ports in the head were the root cause? He also mentioned that my left head ran hot as evident by the coloring of the bottom of the valves.
Prior to a head gasket repair job you must be prepared which I was not 100%. So, here are some things you need for a smoother job:
• Buy everything you need from the store the first time. (Not run back and forth borrowing someone else’s car.) Materials and parts:
1. Head gasket set
2. New head bolts
3. New exhaust manifold bolts (You will break heads of a few bolts.)
4. Thermostat
5. New coolant hoses (If needed.)
6. Ten feet of vacuum hose and connectors that fit on the vacuum tree.
7. New belt (If needed.)
8. Coolant
9. Oil, filter, air filter
10. PCV valve
11. Plugs and wires (If needed. I did not need them because I replaced them a few weeks prior.)
12. Liquid wrench (For the hard to loosen bolts.)
13. Parts cleaner (To soak fuel injectors and other greasy dirt parts)
14. Engine gunk cleaner (While your heads are at the shop, clean, clean, clean.)
15. Electrical parts cleaner. (Plugs and socket will have grease and dirt all over.)
16. Electrical tape and butt connectors (You will find frayed wires to tape up and possibly re-wire.)
17. Zip lock bags with a white area to write (To store small parts and other bolts)
18. Masking tape and a Sharpie (To label bags, vacuum hoses, electrical connectors, etc.)
19. Pans and buckets (To drain coolant and oil)
20. Rags
21. Cardboard box (To store parts.)
22. Go-Jo and fingernail cleaner (Your wife or girlfriend will complain.)
• For those who are tool limited, here are the tools you need:
1. Set of 1/4, 3/8, 1/2 inch metric sockets and ratchets
2. Wrenches of all sizes.
3. 3/8 to ½ inch socket adapter
4. Torx size 55 (For head bolts.)
5. All socket extenders sizes
6. Torque wrenches – ft and in pound (THE VERY MOST IMPORTANT)
7. Swivel socket (To loosen and tighten some exhaust manifold bolts through wheel well.)
8. Adjustable wrench
9. Screw drivers – flat tip and cross tip various sizes
10. Regular pliers
11. Needle nose pliers
12. Wire cutters and strippers. (For those wires who need to be re-wired.)
13. Wire butt connector squeezer (The exact name escapes me.)
14. Vise grips.
15. Small hack saw (For those stubborn exhaust bolts.)
16. Drop light. (You will find yourself working in the dark.)
17. Digital volt meter (To test electrical/electronic components.)
• Despite what you got at the parts store and you think you got everything, you don’t. Have a small pad of paper and pen and soon as you need something next time you need to run to AZ or Advance Auto or junk yard, write it down.
• As I was disconnecting the two O2 sensors, I tore off the internal wires on the top magnetic part of the CMP. I had to go to junk yard and find one. (They are a pain in the butt to reach.) AS SOON AS YOU REMOVE THE UPPER INTAKE MANIFOLD, DISCONNECT FUEL INJECTS ELECTRICAL CONNECTORS, O2 SENSOR CONNECTORS, AND CMP CONNECTOR.
• I did not label all the vacuum hoses. The ones I did, I used a non-permanent marker and I find those difficult to read when re-assembling. USE A PERMANENT MARKER AND LABEL ALL WIRES AND LINE.
• Check resistance of the fuel injectors, ignition coils, and emission parts DVM. Consult Haynes manual for specs
• While you are waiting for your heads to be checked and cleaned, (or new valves in your head), clean everywhere in the engine compartment, electrical connectors, repair wires, parts and bolts that you took out
• Be familiar with the operation of torque wrenches and settings.
• Make sure all gaskets are facing the correct way.
• I had to take off the shroud for the AC heat exchanger out so that my torque wrench fits 90 deg from the very far and inner right corner head bolt
• Once you hand tighten head and lower intake manifold bolts, take a rest and clear your mind. The most important step is tightening heads and lower intake bolts according to specific foot or inch pounds. If you tired and frustrated you will mess up.
• Tighten the head bolts an addition 90 degrees can be difficult if you are tired. Take another break. TO MAKE SURE YOU GO 90 DEGREES AND NOT UNDER OR OVER, TAKE A SHARPIE AND MARK THE HEAD SIDE OF THE HEAD BOLTS. THEN PUT A SHARPIE MARK ON THE HORIZONAL HEAD 90 DEGREES FROM THE HEAD SHARPIE MARK. AS YOU TIGHTENING THE 90 DEG STEP, LINE UP THE TWO MARKS SO YOU KNOE YOU DID 90 DEG.
• Really tighten the exhaust manifold bolts. It’s hard to get a torque wrench in the tight spaces. Again take a break and rest your arms and make sure those bolts are tight – I mean tight.
• Once put together and ready to fire her up, take a 20-30 minute break and recheck all electrical connectors and vacuum lines including the PCV valve and its hose.
• Once you fire her up, she will run rough. At this point it’s just tinkering and finding little problems.
I think my root cause were coolant sleeves and ports in heads and engine block. Lots of gunk came from the top of engine block coolant plugs when heads were removed. But what caused the coolant loss is a mystery to me. Perhaps a good coolant flush would have solved most of my problems, but that would have been a temporary fix. So I believe I did make the right decision to take heads off and get them checked and cleaned.
Fearing I had a cracked block, I took them to a machine shop that specializes in engine rebuilds. Surprisingly there were no cracks. The guy at the machine shop said they were the dirtiest heads he has seen in years. Possible clogged coolant ports in the head were the root cause? He also mentioned that my left head ran hot as evident by the coloring of the bottom of the valves.
Prior to a head gasket repair job you must be prepared which I was not 100%. So, here are some things you need for a smoother job:
• Buy everything you need from the store the first time. (Not run back and forth borrowing someone else’s car.) Materials and parts:
1. Head gasket set
2. New head bolts
3. New exhaust manifold bolts (You will break heads of a few bolts.)
4. Thermostat
5. New coolant hoses (If needed.)
6. Ten feet of vacuum hose and connectors that fit on the vacuum tree.
7. New belt (If needed.)
8. Coolant
9. Oil, filter, air filter
10. PCV valve
11. Plugs and wires (If needed. I did not need them because I replaced them a few weeks prior.)
12. Liquid wrench (For the hard to loosen bolts.)
13. Parts cleaner (To soak fuel injectors and other greasy dirt parts)
14. Engine gunk cleaner (While your heads are at the shop, clean, clean, clean.)
15. Electrical parts cleaner. (Plugs and socket will have grease and dirt all over.)
16. Electrical tape and butt connectors (You will find frayed wires to tape up and possibly re-wire.)
17. Zip lock bags with a white area to write (To store small parts and other bolts)
18. Masking tape and a Sharpie (To label bags, vacuum hoses, electrical connectors, etc.)
19. Pans and buckets (To drain coolant and oil)
20. Rags
21. Cardboard box (To store parts.)
22. Go-Jo and fingernail cleaner (Your wife or girlfriend will complain.)
• For those who are tool limited, here are the tools you need:
1. Set of 1/4, 3/8, 1/2 inch metric sockets and ratchets
2. Wrenches of all sizes.
3. 3/8 to ½ inch socket adapter
4. Torx size 55 (For head bolts.)
5. All socket extenders sizes
6. Torque wrenches – ft and in pound (THE VERY MOST IMPORTANT)
7. Swivel socket (To loosen and tighten some exhaust manifold bolts through wheel well.)
8. Adjustable wrench
9. Screw drivers – flat tip and cross tip various sizes
10. Regular pliers
11. Needle nose pliers
12. Wire cutters and strippers. (For those wires who need to be re-wired.)
13. Wire butt connector squeezer (The exact name escapes me.)
14. Vise grips.
15. Small hack saw (For those stubborn exhaust bolts.)
16. Drop light. (You will find yourself working in the dark.)
17. Digital volt meter (To test electrical/electronic components.)
• Despite what you got at the parts store and you think you got everything, you don’t. Have a small pad of paper and pen and soon as you need something next time you need to run to AZ or Advance Auto or junk yard, write it down.
• As I was disconnecting the two O2 sensors, I tore off the internal wires on the top magnetic part of the CMP. I had to go to junk yard and find one. (They are a pain in the butt to reach.) AS SOON AS YOU REMOVE THE UPPER INTAKE MANIFOLD, DISCONNECT FUEL INJECTS ELECTRICAL CONNECTORS, O2 SENSOR CONNECTORS, AND CMP CONNECTOR.
• I did not label all the vacuum hoses. The ones I did, I used a non-permanent marker and I find those difficult to read when re-assembling. USE A PERMANENT MARKER AND LABEL ALL WIRES AND LINE.
• Check resistance of the fuel injectors, ignition coils, and emission parts DVM. Consult Haynes manual for specs
• While you are waiting for your heads to be checked and cleaned, (or new valves in your head), clean everywhere in the engine compartment, electrical connectors, repair wires, parts and bolts that you took out
• Be familiar with the operation of torque wrenches and settings.
• Make sure all gaskets are facing the correct way.
• I had to take off the shroud for the AC heat exchanger out so that my torque wrench fits 90 deg from the very far and inner right corner head bolt
• Once you hand tighten head and lower intake manifold bolts, take a rest and clear your mind. The most important step is tightening heads and lower intake bolts according to specific foot or inch pounds. If you tired and frustrated you will mess up.
• Tighten the head bolts an addition 90 degrees can be difficult if you are tired. Take another break. TO MAKE SURE YOU GO 90 DEGREES AND NOT UNDER OR OVER, TAKE A SHARPIE AND MARK THE HEAD SIDE OF THE HEAD BOLTS. THEN PUT A SHARPIE MARK ON THE HORIZONAL HEAD 90 DEGREES FROM THE HEAD SHARPIE MARK. AS YOU TIGHTENING THE 90 DEG STEP, LINE UP THE TWO MARKS SO YOU KNOE YOU DID 90 DEG.
• Really tighten the exhaust manifold bolts. It’s hard to get a torque wrench in the tight spaces. Again take a break and rest your arms and make sure those bolts are tight – I mean tight.
• Once put together and ready to fire her up, take a 20-30 minute break and recheck all electrical connectors and vacuum lines including the PCV valve and its hose.
• Once you fire her up, she will run rough. At this point it’s just tinkering and finding little problems.
I think my root cause were coolant sleeves and ports in heads and engine block. Lots of gunk came from the top of engine block coolant plugs when heads were removed. But what caused the coolant loss is a mystery to me. Perhaps a good coolant flush would have solved most of my problems, but that would have been a temporary fix. So I believe I did make the right decision to take heads off and get them checked and cleaned.
