[Gyoas759]

I'm in need of a new intake manifold for my 77 coupe. It's a 2.8 V6 and the current manifold is cracked so coolant is leaking onto the engine block. How hard is it to swap the manifold myself. Am I correct in assuming I'll need a torque wrench etc. to do this? Just trying to decide if I I should try it myself or just pay a mechanic to take care of it for me. Thanks!

[74stang2togo]

An intake manifold isn't that hard to do.

Here's what you'll need:

1. Repair manual for the car. (Can be a Ford service manual or a Haynes/Chilton type manual.)

2. A roll of paper towel (either the blue shop towels on a roll or thick white ones like Brawny, you don't want the cheap ones for this job!)

3. A 3/8" drive ratchet, a couple of extentions (3" and 6" should be good) a 3/8" drive metric and SAE socket set (everything from 6mm to 19mm and 1/4" to 3/4" if possible, some may have to be purchased in 1/4" drive and used with an adapter) you may also want a 3/8" drive flex joint. You may also want a set of wrenches and/or a good adjustable wrench.

4. A pry bar, you can get by with a really big flat-blade screwdriver, but having a good pry bar would be better.

5. A scraper. This doesn't have to be fancy, the cheap $0.50-2.00 kind that is little more than a handle and a razor blade under the counter at a lot of the chain parts stores works well.

6. A torque wrench, with the right sized socket for the intake manfold hold down bolts.

7. ALL of the parts: Intake gaskets, gasket sealant (Silicone RTV and Shellac), a thermostat and gasket (thermostat and gasket is $3-5, do it while you're in there), carburetor base gasket and EGR plate gasket (you might not need the EGR one, can't remember) fresh oil and filter (you WILL get coolant in your oil if this is your first time doing this, heck, even seasoned pros do sometimes! just change it when you're done, save yourself the potential headache! lol) two gallons of coolant, teflon tape or sealant, some chalk or tape to mark the distributor position if you have to pull it, and while you're at it a fuel filter (gonna have to disconnect the hose that goes to it anyway, might as well change it while you're in there too!) a can or two of carburetor cleaner... oh, and a pen and paper to take notes! Another helpful item is a shop vac.

Okay.... if you're still with me, here's how you do it.

1. disconnect the battery (call me crazy, but I do it for this job... sometimes I actually have to (my Mustang II's got a negative cable that runs to the intake, factory did it). Then drain the coolant.

2. Remove the air cleaner and take notes (where the pen and paper comes in) of where the various hoses, linkages, cables, and wires go.

3. Carefully disconnect said wires, linkages, cables, and hoses (some will be brittle, they could be as much as 30 years old!) and set them aside.

4. Remove the four nuts or bolts holding down the carburetor and set it in a save place, being careful not to bend any of it's linkage.

5. Set the new manifold beside the old one. Remove the brackets and fittings from the old one and transfer them to the new one, don't tighten anything down on the new one yet though, you may need to move/remove some of these things to put in the hold-down bolts.

6. Disconnect the upper radiator hose and move it out of your way. There will probably be some coolant left in it, so watch for the inevitable splash at your feet.

7. Remove the thermostat housing and use the scraper to clean it's mating surfaces as well as the ones where it mounts on the new intake.

8. Start removing the intake manifold hold down bolts, noting where they go (you can stab them into a box in order if you'd like so that they don't get lost and are lined up for you when you need them again.

9. Once all the bolts are out, gently push the edge of the pry bar through the sealant at the front edge of the intake where it meets the block, if you can make any progress there, keep pushing, rocking the pry bar back and forth and/or up and down until it gets through there, once it's in, slowly pull back on the pry bar, the intake should "pop" once it does, any coolant left in the passages just went into your oil, but don't worry about that, that's why we're going to change it later!

10. Now that the intake manifold is loose, slowly pick it up (straight up if possible) and set it aside. Now is where the paper towels come in, stuff one in each of the intake ports and coolant passages on the heads (carefully, you want the paper towel to keep debris out, not push any in!) Then line the lifter valley (the part of the engine under the intake manifold) with paper towels.

11. Use your scraper to scrape every part of the gasket mating surfaces of the heads, the new intake, and the block clean, get all as clean as possible, they need to be almost perfect. You can use the carburetor cleaner to help soften up old gasket material.

12. carefully remove the paper towels from the ports and passages, so that any debris falls into the paper towels lining the lifter valley.

13. Carefully lift the paper towels out of the lifter valley so that no debris falls into the engine. If you have a shop vac, it's not a bad idea to use it to suck any possible debris from the intake ports and coolant passages (note, a good and powerful shop vac WILL suck up oil and/or coolant, so do it without the filter using only a wet/dry shop vac! If using the shop vac, wipe dry any surface that gets wet, spraying away any oil that gets on a mating surface with the carb cleaner)

14. Coat the mating surfaces of the heads with shellac-type gasket sealant, place the intake gaskets on there.

15. Your intake gasket kit probably came with cork pieces to place at the front and rear of the block, throw them away. Put a nice THICK bead of Silicone RTV there instead.

16. After everything has cured the recommended time (you did read the tube and bottle, right??? It's usually 15 minutes) VERY gently set the intake down, so as not to disturb the gaskets, and place one bolt in each of the four corners, but don't tighten them more than one or two turns, they're just going in to hold it all in place.

17. This is where the repair manual comes in... You need to turn to their instructions on how to do this, because they'll have the torque specs and the tightening sequence for you, Do as your manual instructs for this part.

18. Install the new Thermostat and gasket along with the water outlet, you can use either type of gasket sealer on this.

19. Install the carburetor using the new gasket and fuel filter. Look inside the carb, if it's black, spray some carburetor cleaner in there to clean it before installing.

20. Reinstall your various cables, wires, and hoses.

21. Change your oil and filter.

22. Fill the system with coolant and water (50/50 ratio unless you live where it gets really cold).

23. Reconnect the battery, start the engine and listen for vacuum leaks (loud hissing or whistling noises) look for obvious signs of coolant or oil leaks, let it run about 30 seconds to a minute total and shut it off, check the oil. If it's milky, than you've got coolant leaking into your oil and need to do it again... if it's still clean, you're good to go on to the next step.

24. Re-start the engine; as the engine warms up, add coolant till the system is topped-off and the thermostat has opened (coolant is flowing through the system quickly).

25. After you've got the cooling system filled up and the engine at operating temperature with no leaks, shut if off, check the oil one more time, if it's still clean, crank her up and take her for a test drive. If it's not still clean or there are leaks, let it cool off and start over.


DISCLAIMER: This is just a generic article on how to do an intake manifold on most OHV V6 and V8 engines. All steps may not be covered for all vehicles. Though I do work on cars for a living doesn't mean I know everything. I always recommend comparing my notes to those in an owner's or service manual, and where my opinions and theirs differ, follow theirs!