Head and Intake gasket replacement question

[borjawil]

94 4.0L.

Having some hard timing finding a solid answer to a few questions. I had white smoke from exhaust with no overheating at first. Then temp rose to about 3/4 7/8 from red line. Drained oil and coolant, flushed coolant. No mixing in either fluid, coolant was dirty. Refilled, ran around the block, overheated again. Milky dip stick. Tells me blown head gasket.

1) for my own knowledge in the future can I get the above symptoms from the intake gasket leaking coolant?

2) do I torque my head first then intake, or both at the same time? Ive seen mixed comments on this and wondering why.

3) RTV black came with gaskets - I've read to use around the coolant passages...intake and head or where?

4) also read to put RTV on four corners of head gasket - i believe this was just to hold in place, but i have locating dowels.

 

[adsm08]

1) You can get oil and coolant mixing on this engine from just an intake gasket. You won't get the smoke from that. Smoke comes from fire, and fire only happens in the cylinder (ideally).

2) You torque them together. If you look at the torque sequence in the manual it says to do them together.

3) I only use it at the corners of the valley.

4) I use copper gasket spray all over the head gaskets, both sides. You don't really need to do anything to hold it in place, as positioning and holding the gasket and head is what the dowels are for.

 

[RonD]

2) lower intake has light torque spec, 24ft/lb
If you are redoing head gaskets then yes you should install the heads and lower intake at the same time
But people do have to replace lower intake gaskets, you do NOT need to remove the heads for this, so you can install the lower intake after heads are torqued down
There is no confusion on this just different starting points, i.e. heads on or heads off

Also use loc-tite on lower intake bolts and then re-torque/check lower intake bolts after a month or so of driving, they tend to loosen up

2) I use the RTV in the lower corners of the intake, none on head gasket, also across the block from corner to corner, front and back, as there is no intake gasket there, and RTV would fill any gaps between surfaces, block and intake

 

[borjawil]

Thanks for the info. Ran into something with the upper intake gasket. Same gasket as the one i took off it 6 holes lines up, but there is not gasket between upper and lower and I can see the opening of the lower intake where there is not gasket..am i missing something here?

 

[RonD]

On the 4.0l OHV there is the Lower intake, then the Fuel Rail, then the upper intake

Unless you plan on changing the injectors or the "O" rings you can leave the fuel rail attached to the lower intake, i.e. leave the 6 studs in place

Only the 6 air passages are, or need to be, sealed, any other openings are on purpose and don't effect engine operation

If you have already removed the fuel rail then you will need a gasket for that, and I would change the "O" rings as well at that point.
After lower intake is installed put ALL the injectors into the fuel rail FIRST then lower fuel rail into place(with new gasket) and guide the injectors into their intake holes.
If you put injectors into intake first then lower fuel rail you will pop off some "O" rings

 

[borjawil]

Sorry its taken me a minute to get back. I saw that the open passages just go to the atmosphere if you will. The actually intake passages are not open. But it looks like my intake gasket was likely the culprit not necessarily the head gasket. Didn't realize a bad intake would cause blown head gasket like symptoms. And of course its happening again.

-Is kopperkoting the intake gaskets ok?
-My lower gasket was a 3 part gasket thats stuck together but would not line up correctly with the bolt holes. I removed the middle portion by cutting along the dotted lines. Not sure if those were to guide for cutting or easier bending.
- If I can kopperkote do I also use sealant on the water passages?

 

[borjawil]

Ok so no coppercote on intakes but as for the RTV application...Do i put it around the water jacket holes or on the entire gasket? Top and bottom? Do I put RTV on the middle of the block and lower intake surfaces where the gaskets don't cover?

 

[black_demon69]

Ok so no coppercote on intakes but as for the RTV application...Do i put it around the water jacket holes or on the entire gasket? Top and bottom? Do I put RTV on the middle of the block and lower intake surfaces where the gaskets don't cover?

rtv at ends in valley between heads, and at corners where intake gaskets and heads meet at corners of valley, you can also use rtv around water jackets if you wish.. copper gasket spray works very well btw.

if not pulling heads just get lower intake gasket set, if pulling heads get head gasket set and head bolts. also if pulling heads get machine shop to check them and count on possibly some broken exhaust bolts.

just did heads on mine all exhaust valve seats were bad 1 head was cracked also needed milling.. all common problems for the 4.0l

 

[adsm08]

If you use copper spray plan on needing some of these the next time you pull your heads. I just had to take the heads off an engine I used that stuff on (had a bad valve that I missed on the rebuild) and I could not get the heads or block cleaned well enough with a razor. Five minutes with that and all was shiny and clean.

 

[borjawil]

With some research I've noticed something. Ive seen 2 piece gaskets that connect at the front and rear of the block. Do i need gasket material or rtv in the middle of the lower intake where it meets the block?

Also why is the lower intake bolts torque so low? I can definitely keep turning easily after 13-18 ft/lb.