I have a shot at a '97 F150, Supercab, 4x4, with a 4.6L engine that according to the current owner has a blown head gasket. He's asking $700 and will throw in the gasket kit.

How much of a "B" is it to replace the head gasket on these "modular" engines? The engine has 213K on it....is it even worth it? Can it be done with the block in the truck or should I remove it on put it on a stand?

I'd love to have a rig with the "newer" body style but don't want to get into a money pit (insert laughter and snickers here).

Seeking opinions and guidance.

Thanks in Advance!!

 

It can be done with the engine still in the truck. It's not entirely clear what the "seller" actually means by "blown" head gasket though. The 4.6, especially the Romeo engine, is prone to leaking oil or coolant through the head gasket. A blown head gasket is much less common. Also, it's not a given that simply pulling the head(s) and changing the gaskets as it's put back together would solve the problem. The suspect head would have to be cleaned, checked for warp/cracks, before reassembly. If the head is not good, after all this, cost becomes the issue.

There are a couple of head gaskets available. One matches the original ( and could leak again ), and the other is a service replacement gasket specifically for heads that are already leaking.

If the truck is otherwise in pretty nice shape, it might be worth the gamble, but you really can't tell now, without doing half the repair job. That kind of miles is tolerable, but also creates a situation that may require replacement of numerous other bolts, hoses, etc., just because it would be easier with half the engine apart.

Dave

 

I just finished an "in truck" head gasket replacement on a 97 4.6 Windsor. It's time consuming but not that bad if you aren't in a rush. It was my fathers truck, purchased new and well maintained but began leaking coolant into the motor and pressurizing the coolant system with 219K miles. He gave it to my son (16, just got his license) and it became our project. Knowing that the truck had never been overheated I took a gamble and replaced the gaskets without remachining heads, doing a valve job or anything else since it was running well even with the leak. The head bolts must be replaced with new, and I chose to put new lifters, cam chains and a crankshaft cam chain sprocket on it due to the mileage. It's only got a couple hundered miles on it since reassembly but I'm super pleased with how quiet and smooth the engine runs. No coolant is being lost and no fault codes have occured. If it turns out the heads are warped and leakage reoccurs I'm sure we can tear it down again in half the time to replace the head gaskets and machine the heads. In our situation the truck is only hauling a teenger to school and back... I figured by the time I spent the extra money to machine heads and rework the valves, seats and springs something in the bottom end of the motor would go bad due to mileage.....if it lets him down he can ride the bus! My advice is go for it. We've got a great running, good looking truck for around $600 in parts / fluids, labor, father/son arguments and memories (like the dipstick tube that broke off in the block then fell into the pan when we tried to remove using an easy out).

 

Sounds awesome whokluvr. I am trying to get to the point of doing mine due to the oil leak into the coolant, but can't seem to get started to try to figure it out.

I have had mild "heating" up - probably due to so much oil in the coolant, but it has never been in the over-heating range.
I will still probably get the heads done, but ... I guess I'll keep the cams that are in it to save money.

Since you went all of the way and had to re-set the timing up, what info or resource did you use to get the new cams and motor all lined up correctly for timing?

Also, was there measurable wear on the cams, cam chains or lifters?

 

I bought a Haynes manual and it contains cam timing info but I didn't use it for my reassembly. I bought 2 different color paint markers to mark crank and cam alignment. After valve cover and front cover removal I set the engine to TDC, compression stroke on cylinder #1 then "painted" a chain link and sprocket tooth that were in mesh on both crank and cam sprockets. I used a different color for each side and also painted some marks on the stretch of chain running opposite the tensioner guide to help with orientation. Since I planned to reuse my cams all I had to do was count the distance (links) between paint marks on the old chains and add paint marks to the new chains and crank sprocket at identical positions. It works when you return the engine to TDC #1 and reassemble the engine with the heads/camshafts setting in the same position as when they were removed. I'd be afraid to do this with the engine in any other position, see below.

Our 4.6 motor is a 2 valve per cylinder, DOHC and I didn't purchase cam holding tools and didn't find then necessary. If you are careful and hang on to the cams using the two holes in the cam sprocket you can release the chain tensioners, remove the chains then allow the valve spring tension to SLOWLY rotate the cam a few degrees until it comes to rest. The problem is you don't know if it came to rest because a valve was hitting a piston. To verify valves weren't touching, I grabbed each camshaft sprocket by hand and turned CW and CCW to verify they weren't bound up on a valve. The right cam could be rotated several degrees either way but the left cam had less clearance in one direction and would touch a valve pretty quick. It had plenty of clearance when turned the other direction. At least I knew valve / piston contact wasn't an issue with the chains removed. Performing this test confirmed I could remove / reinstall a fully assembled head and not be at risk of valve piston contact. At reassembly be prepared to use the cam sprocket pin holes to rotate the cams against the springs in order to match your paint marks on the teeth and chain links.With this method I had no problems with the valves touching pistons at any point of the repair when at TDC on number 1.

As far as wear I saw nothing I considered unusual. No discoloration or galling, I measured cam lobes and bearing OD's for comparison to each other and all were consistent. I replaced the lash adjusters (lifters) because there was a considerable difference in feel when collapsing them on my workbench. There were noticeable chain marks on the crank sprocket teeth but the teeth didn't appear to be thinner or hooked when compared to the new one so it may have been fine. Replacing the chains just seemed to me like a good idea and since the crank sprocket has turned twice as many times as the cam sprockets I thought replacing it made sense to.

If I had to do anything over it would be to put more effort in cleaning the engine compartment before teardown. In addition to the motor, we spent a LOT of time cleaning the engine compartment prior to reassembly.

Have fun!