@@1990 Ranger 4x4 4.0L "BLOWN HEADGASKET"@@

ANY SUGGESTIONS ARE APPRECIATED.

I just purchased a 90' Ford Ranger XLT 4x4 4.0L Supercab. The truck was sitting for about a year right before I purchased it according to the previous owner. It was driving fine, I drove it from San Diego to Moreno Valley (2 hour drive one way) with a full load in the back e.g. small 4cyl engine and misc car parts.

Anyways, its smoking white and smells like its burning coolant. Radiator needs to be filled after every drive. I now have it parked. Pretty sure its a blown Head gasket. My mechanic did a compression test and #4 cylinder is low. I forgot to ask what the compression numbers were.

My question is, do you all think its worth rebuilding?? I've been researching & found that my 4.0L is some what difficult to rebuild. If I'm wrong, let me know. This is my first Ford truck I've ever purchased. What would be the cheapest way to repair it. Should I ONLY replace the head gasket and of course checking & rebuilding the heads. Or, do a COMPLETE rebuild from new pistons,rings, oil pump etc.....? Does anyone know a good crate engine seller for replacement and would that be the best route to go? Any advice appreciated. What are my cheapest options????? Thanks.

4.0l OHV engine, 1990-2000, is fairly easy to rebuild, so that info is incorrect.

4.0l SOHC engine, 2001-2012, is more complicated with over head cams

4.0l OHV would often crack a head if over heated, same symptom as blown head gasket.
And the white smoke with sweet smell indicates you have one of those issues.

If there is no sign of coolant in the oil, and mileage on engine is less than 300,000 then I would just pull the heads and have them pressure tested then reinstall new head gaskets.
4.0l OHV is a high mile engine so no reason to do the lower end if mileage is under 300k.
If coolant does get into the oil then that can ruin bearings fairly fast so rebuild would be needed, so if that hasn't happened yet then I would not drive it much more

It is not hard to pull the heads in the vehicle, just wrench work.
If truck is running then stop by an exhaust shop and tell them you will be pulling the heads, have them loosen and replace any broken exhaust bolts, then snug them back up for the drive home.
Exhaust bolts account for more lost hours and trips to parts store than any other fastener on a vehicle, lol, let the experts spend 60mins to save you 6+ hours

You will need
Head gasket kit, includes intake and exhaust gaskets
Head bolts, these can not be reused
Coolant, refill engine with water after reassembly, and run it that way for a few days, checking for leaks, then drain and fill with the new coolant, this also works to dilute and flush out old coolant.
New thermostat and rad cap
Oil and oil filter.
New water pump is optional but not a bad idea

New head??
Machine shop can pressure test heads, clean and surface them, also install the new valve guide seals that come with head gasket kit.
You do not need to do anything to the valves unless there are obvious problems.

The 4.0l heads crack between valve seats, you can sometimes see this crack as a line between the valves so no doubt that head is cracked, but it can be almost invisible in some cases, so if line is there in one head replace that head for sure, but pressure test other head just to be safe.
New head will already be cleaned and surfaced, so if crack is there then you only need to pay for servicing 1 head

Special tools needed
Torque wrench
Ford fan clutch tool set, or strap wrench and thin crescent wrench can work with some effort
Torx T55 socket for head bolts

Drain oil AFTER engine is mostly back together(heads and intake installed) but before starting it, and put in fresh oil and new filter.
You do this AFTER because pieces of gasket and ??? will fall into the oil pan while disassembling and reassembling, if pan is empty debris will just sit there and get mixed in with new oil when added, if old oil is there it will float in the oil and most will come out when oil is drained.

Machine shop can take 2 or 3 days
First time head removal shouldn't take more than 10 hours, 6 hours if you have done it before, take LOTS of pictures of hoses and wiring before removing, easy to do and then there's that old "Picture is worth a thousand words thing"

8 hours reassembly, with pictures

If you can get heads off and to machine shop on Wed. afternoon or Thursday morning then you could get them back by Fri. afternoon or Sat. morning.

Good read here on the 4.0l OHV changes over the 10 years: http://www.therangerstation.com/tech_library/40rebuild.shtml

Ron D,

Thank you very much! This is good news. I don't see any oil & coolant mixture yet. Also, I think I have an exhaust/muffler leak. Going to the exhaust shop would be a good thing. I can knock out two birds with one stone; exhaust bolts & exhaust leak.

What are the best, top of the line, reliable head gaskets for these Ford Rangers?? Ford Motorcraft? If Ford still makes them. Money is no option. Thanks again for the info.

I have used Felpro gaskets and gasket sets over the years, never been disappointed

i have a 91 stx ranger and had the same problem. i put all new parts on the top end of the motor. replaced both heads, valvetrain, etc. i ran it hard for another 50-75k all over the east coast from florida to maine with work. truck had finally had enough and is sitting silently and calmly on a v8 or diesel.

i would also recommend doing a full engine flush..oil flush with a decent detergent. flush the cooling system and check for debris in your heater core. i also went ahead and replaced frewewze plugs with brass. as far as headbolts go you definitely need to replace them...however i would not go with a super high dollar brand kit for this motor. i find it amazing how some companies put a price on hardware kits such as headbolts. id rather order the same bolts from mcmaster carr