Coolant thru intake

[rnscustom]

I have a coolant leak into the engine shown by white smoke from the exhaust . At this point I think it’s coming from the intake . I just did a timing chain but I ran it for a long time with the engine piping farting and stalling ( at least a month ) anyway ran decent after till it started the white smoke . This is after my son held a rag over the car starving it a few times to clean it ???? . Good compression, holds pressure when cool . Thinking it’s intake . Can that bypass under the carb leak into intake ? Thanks , Richard p.s. I’m registered but couldn’t find where to sign in ( been a while )

[datzenmike]

 

 

When you had the head off I (again) assume that you took the intake off? Have you tried checking and tightening the mounting bolts? 12-15 ft lbs. Don't over tighten, the head is soft aluminum.

 

Head was torqued with a torque wrench in this order?

 

R..A..D

8......7

4.....3

2.....1

6.....5

10...9

 

to 20 ft lbs

then 40 ft lbs

finally to 60 ft lbs

 

[rnscustom]

Thanks datzenmike . I didn’t remove the head or intake . Timing cover and valve cover only 

[datzenmike]

Of course, I always associate timing chain with blown head gasket.

 

I guess the rad needs topping up regularly?

 

 

Well leaking intake or head gasket. Pull all the plugs and keep in order. Inspect them. Are they all the same, or are those from one cylinder much cleaner than the others?

[rnscustom]

Thanks datzenmike , all the same , compression test was good in all cylinders , pressure test was good while cold and running showed no fluctuation in gauge needle . She runs at a real high idle which I’m thinking is an intake leak , I did not spray the intake as I pulled the plugs to do the compression test which was good . In cranking the last time she locked up on me ( thinking hydro lock ) from the front I pulled one plug at a time and tried cranking . She unlocked on plug three and rotated , I didn’t notice if water spewed out as I couldn’t see from the drivers seat but I’m assuming it did as it was free then . My big question before I pull the intake is if it it is possible for water to be coming in from that water port below the carb on the manifold ( I haven’t look to see that it actually exists only read it’s there . I’m sure it’s typically sealed off from the inner of the intake but is there some sort of a freeze plug there that could fail or is it cast over and just a port in the casting , I’ve never had the intake out . I did do a head gasket in my last 84-1/2 st but I don’t recal looking under the carb 

[datzenmike]

On the head, and the intake, there is a small port below each intake for coolant to circulate. If the intake gasket has failed, coolant can be sucked up and into the intake port. Oh yes. Coolant is collected from all four intake runners under the carburetor and along with water from the heater is piped down to the lower radiator hose and back into the engine.

 

Z24, thought the Z22 is very much the same.

 

A compression test may not show up a head gasket leak into the cooling system.

 

The 'freeze plug' is only a covered opening used to remove the casting sand after pouring the manifold.

 

Were the number 3 plugs cleaner than the rest? Coolant turned into steam is an excellent cleaner.

[rnscustom]

All plugs looked the same . I’ll attack the intake gasket and see if that works  first ( keep it simple ) so that casting plug ever fail that you heard of and is it in the carb base area and could possibly fit out like a freeze plug or not likely . Thanks for the picture and all this quick responses . Great asset to this forum and all the members . I’m going to try getting on here more often , life gets in the way . I have a few projects and none get done but this is my daily . Thanks , Richard 

[datzenmike]

I imagine the plug opens out into the intake plenum. If it failed there would be a huge vacuum leak and engine wouldn't run. If it opens out into the coolant passages it would just leak outside.

 

Absolutely do the intake gasket first.

 

Have you driven it enough to notice the rad needing to be topped up? Odd that changing the timing cover results in a coolant leak on the intake. (or HG) Vehicle exhaust does get noticeably steamy in cold weather. Very much so on start up and usually lessening once warmed up.

[rnscustom]

Ok so the intake is off , 1 and 4 intake ports are washed 2 and 3 are black . Not sure if there is a way for water to enter under the carb but at this point looks like a head gasket???

[Stoffregen Motorsports]

15 hours ago, datzenmike said:

 

 

When you had the head off I (again) assume that you took the intake off? Have you tried checking and tightening the mounting bolts? 12-15 ft lbs. Don't over tighten, the head is soft aluminum.

 

Best cure for this is to convert the manifold mounting hardware to studs.

[rnscustom]

I posted up again , maybe after you wrote this , yes , she’s a pain to remove , wrench only at the bottom bolts unless I missed something . The intake gasket looked fine , not anymore of course , didn’t see anything that looked damaged . Looks like it’s a head gasket 

[datzenmike]

1 hour ago, rnscustom said:

Ok so the intake is off , 1 and 4 intake ports are washed 2 and 3 are black . 

 

What does this mean, washed?? Cleaner than 2 and 3??? This might indicate that 1 and 3 are leaking coolant in and cleaning the ports.

 

 

Again are you loosing coolant and needing to top the rad up? Steamy exhaust can just be colder weather where it's more noticeable.

[rnscustom]

Yes loosing coolant , quite a bit , tried to start her after I got her to the shop and she locked again ( hydro I assume . Plugs are all black , 4 looks wet 

[datzenmike]

OK better to check an know for sure. Were any intake bolts loose?

 

Well if you think the intake gasket was ok then I guess the head gasket. 

 

You know how to secure the chain tensioner so you don't loose it and have to take the front off the engine again???

 

[rnscustom]

Yes , done head gaskets before in my last ones , vdont remember the measurements but I’ll look it up 

[rnscustom]

No one has come back with any possibility it could be coming from any casting plug in the intake manifold so all that’s left is the head , I’m pulling that now so new head also 

[Stoffregen Motorsports]

Could be a rotted out intake manifold, but I've never seen one go bad. But then again, these parts are now 50 years old. Anything can happen.

[datzenmike]

There would be no reason to have any connection between the intake runners and the coolant runners, and then have to plug them.

 

With the intake off, stand it with open ports up, fill the coolant passages with water and leave over night. In the morning see if any water in the intake runners by laying it down in the correct upright position. It's unlikely unless cracked. That's more likely than eroded away.

[rnscustom]

Thanks guys , my first suspect is the intake ( like I was mentioning in the first post my son held a rag over the top and starved the carb for air , thinking it would help the carb spray cleaning process ) started with the white smoke after that . Head is sitting there waiting for the gasket . I’ve left the wood wedge in the chain for a few days in the past only to have it slide down a little , was a bear to pry it up and slide it on . Good idea on the water . It’s all attached right now so I may throw some good duct tape over them and try force feeding . I’d didn’t start smoking till it was a little warm and she held pressure while cold so that may not work unless it’s hot . Thanks again , Richard   Head will be off soon so hopefully it’s a gasket

[rnscustom]

ok, head is off , water in #4 and gasket blown right at water passage . Exciting news !!! . Would this explain the high compression in #4 210 and all the others in the 160-180 range , an why would it be more not less ?? Che fact that the water is acting as a seal 

[datzenmike]

If there was a puddle of water taking up space then yes the compression would be higher.

 

Check your oil. If run long enough compression will squeeze water or steam down past the rings and it will mix with the oil. If it looks like coffee with creamer then it needs to be changed along with the filter.  

[rnscustom]

Looks good , I’ll probably change it soon though , just did the chain and did the oil then . Interesting but when a had the timing cover off the engine had a remanufactured by Nissan sticker on it . Likely that that could have been done many years ago . This truck is registered 1982 but it has the 2.4 and a hardbody bed also a Nissan grill . I suspect the only thing 1982 is the vin . Head gasket never showed today so not back together . Thanks for everyone’s help here . I’ll follow up when she’s back together . 

[datzenmike]

Maybe the dealer replaced the engine with one from Nissan. I was wondering why a Z22 would blow the HG and that explains it. The Z24 is known for this problem at 100k intervals. The preventative, is to once a year re-torque the head bolts. When the engine is cold, loosen one bolt only and immediately tighten to 60 ft lbs. Do one bolt at a time any order you like.

[rnscustom]

My first Datsun was a 1982 I believe , had the z22 , that had a semi dead #4 in it when I gave it to my brother . Drove it till 1987 I think . This might belong in another section , bought it brand new white with blue interior no bumper , no radio . Big sale they year I think it had big block numbers on it $2999 , anyone remember if that is correct for the cost and year of that . Thanks , Richard 

[rnscustom]

Still the same torque specs as stated before , book says 22 then 58 loosen and repeat