Leak between head and block

[Onion]

This is pretty recent. I often pop my hood just to take a gander and see how things are going. In the past week or two, this happened (since the last time I took a look around). I'm assuming its water, since there's rust, but I'd need an expert opinion on this as this is way above my level of expertise.

 

 

I took the car in this week for a carb tuneup (I'm absolutely useless at tuning carbs and can't figure out how to tune my Holley). The guy mentioned lower vacuum on one of my cylinders. He didn't do a compression check, but he said that the car wasn't really firing on all 6, but wasn't misfiring. If it is this cylinder that's having issues, how could that be related to the rust? 

 

Thanks. 

 

Edit: Forgot engine specs. Again. This is an L24, E88 head, hot cam.

Edited September 25, 2013 by Onion

[Nelatl]

I'm no expert but here are the things I would do( in order of difficulty)

1-check coolant for oil and oil for coolant

2- re-torque head bolts

3-compression test

 

My head did the same thing once after I changed a head gasket(first time) and after a re-torque of the head bolts no more leak problem. Does the car smoke at all?

Edited September 25, 2013 by Nelatl

[Onion]

I'll get right on that, thanks! 

 

I haven't touched the head bolts at all, so it would be somewhat peculiar for that to be my problem all of a sudden. Hopefully that's not it, because chasing down the cause of that might be quite a hassle.

 

The majority of the time, it burns clean. Rich, but no smoke. On cold starts (not very cold in Florida, though), it'll smoke white. It smells odd, but it doesn't smell sweet, so I don't think its burning coolant. It does burn oil very slightly, but not enough for the exhaust to smoke blue. Sometimes it'll smoke a little (barely visible) blue but once it warms up, it goes away. 

[Nelatl]

Well good luck man. These cars will keep you busy

[Onion]

Well good luck man. These cars will keep you busy

 

Thanks. Surprisingly, mine hasn't been too much of a pain lately. I changed the spark plugs, adjusted the timing, and that's about it. The problems started piling up today and yesterday though lol, back to work!

[BluDestiny]

According to the fsm the head stud torque should be checked every so often. But personally I never did either. When is the last time you changed your coolants?

 

Something similar to that happened to me like 5 years ago, in my 260z. It just felt low on power and when started acted like crap. turned out my head gasket almost randomly blew, so that the compression in the number 5 cylinder was lost and coolant was getting through and leaking. 

Edited September 25, 2013 by BluDestiny

[Onion]

I'll give them a check, just for safety. 

 

I flushed the radiator no more than 2 months ago, which was about 1500-2000 miles (tops). I also changed the oil the same day. Oil was black was a bit black and nasty, coolant was fine. I'm about to change the oil again, as its already black and nasty, even though I've topped it up with a full quart since the oil change. It used to burn a bit more oil than it does now, but tuning it and fixing the timing made it better. 

 

Hopefully it's not a head gasket (my worst fear, as well as O rings), because that takes my only ride out of commission for a while if I do it myself, or a big chunk of cash if I take it to a shop. 

 

I checked the oil and coolant, both are okay. I can't REALLY see into the radiator (aluminium performance radiator) because the way its designed restricts your vision, but the radiator cap had some coolant on it and it looked alright. Should I drain and refill the coolant just for safety and take a better look at it?

Edited September 25, 2013 by Onion

[NewZed]

The spot where the water runs down the block may not be where the leak is, depending on gravity and flow path. 

 

I had a water leak at the back of an N42 head, only from the coolant system outward, no internal leakage.  A tube of Bar's Stop Leak fixed it for while, until the material eventually extruded out of the gap.  If the gaps are small enough, it might work for you.

[Onion]

Update: These spark plugs are three weeks old, correctly gapped (of course), and have about 500 miles on them, tops.

 

 

Disregard the numbers on them, I messed up. I didn't know what where cylinder 1 was, so I just started from left to right, standing on the passenger side. Plug number 5 (which is actually number 2) is wet with what seems to be oil. Plug number 4 (actually 3), is a little wet as well. They're only wet around the threads, but the tips are good (probably because the engine toasted all the oil off them as it ran?). I checked number 3 as well (really number 4) and it was moist as well, but not as much as these two. Could someone provide some insight about possible sources of oil?

[djwarner]

Hi Onion,

 

I've been facing a similar problem, but oil rather than coolant. The previous owner got the car back on the road after 2-3 years and was fighting a coolant leak in the same spot. He said he eliminated it by re-torqueing the head bolts. This controlled the coolant leak but I am now consuming a quart of oil every 300 miles.

 

It was a real head scratcher for a while. Replace the valve guide seals and tightened the belly pan bolts. The only evidence of oil leakage was a stain above the oil filter. It appeared so thin, I thought it was spillage when I set the valve clearance. After several high detergent oil changes hoping to free stuck oil control rings, I did a compression test. Not only was the compression uniform, it exceeded specs, suggesting carbon buildup in the combustion chamber or a shaved head from a re-build 10 years ago.

 

I did a couple Seafoam treatments hoping to burn out the excess carbon. After a treatment, I drove the car just long enough to get everything warmed up. Parked the car and popped the hood. The damp spot was soaking wet and oil dripping down to the belly pan. Seemed that the highest oil pressure occurred at highway speeds before the oil finally thinned out. This is when oil pushed past the head gasket at the oil passage feeding the head. 

 

I am scheduled to pull the head tomorrow. One thing I've learned is that there have been three head gasket design variations by Nissan. It seemed they upped the head bolt torque requirements with each revision. Also some gasket designs required re-torqueing after the head gasket took a set after 1500 miles. So re-torqueing may bring you relief. 

[srgunz]

This is pretty recent. I often pop my hood just to take a gander and see how things are going. In the past week or two, this happened (since the last time I took a look around). I'm assuming its water, since there's rust, but I'd need an expert opinion on this as this is way above my level of expertise.

 

 

I took the car in this week for a carb tuneup (I'm absolutely useless at tuning carbs and can't figure out how to tune my Holley). The guy mentioned lower vacuum on one of my cylinders. He didn't do a compression check, but he said that the car wasn't really firing on all 6, but wasn't misfiring. If it is this cylinder that's having issues, how could that be related to the rust? 

 

Thanks. 

 

Edit: Forgot engine specs. Again. This is an L24, E88 head, hot cam.

 

You guys run just straight water in Florida???

[dexter72]

While your checking compression, i would do a valve adjustment.

[Xnke]

The cause of the headgasket seepage is not retorquing your headbolts. I went through this, having never retorqued the headbolts on any Datsun I'd worked on except the Z24; but the FSM DOES call for it to be redone every 15K miles. TonyD explained it as taking up the embedment of the gasket, and the aluminum cylinder head. Once I started re-torquing the bolts, the coolant leak went away and has never been back.

[seattlejester]

Worse case, blown head gasket.

Middle case leaking gasket via the same reasoning as above, if the motor was rebuilt recently or neglected for a while, it may need a retorque to take up the slack.

Best case, worn coolant pipe seeping ever so slightly and running a ring around the seam. Check the heater hoses and the carb heating lines.

 

Keep in mind you will need a torque wrench and a 3/8th drive allen set to retorque the head, can be had for ~20$ for both at harbor freight I believe.

If it is a blown head gasket don't fret too much, you can still do the head gasket job in a day. The worst bit will be taking the manifolds off and making sure you have the chain tensioner installed correctly. 

[Onion]

You guys run just straight water in Florida???

 

I've got coolant mixed in there. 

 

While your checking compression, i would do a valve adjustment.

 

My engine started to make a clicking sound, so yeah, it's time for a valve adjustment. I picked up a feeler gauge when I went to get a plug gap tool knowing I'd have to do it soon. 

 

The cause of the headgasket seepage is not retorquing your headbolts. I went through this, having never retorqued the headbolts on any Datsun I'd worked on except the Z24; but the FSM DOES call for it to be redone every 15K miles. TonyD explained it as taking up the embedment of the gasket, and the aluminum cylinder head. Once I started re-torquing the bolts, the coolant leak went away and has never been back.

 

It's very possible the previous owner put a new head gasket on, he did a lot of engine stuff and never drove the car. I need to get a better torque wrench. Today's my day off, I'll pick it up after I'm done getting my tires installed and give it a try. Hopefully that takes care of it.

 

Worse case, blown head gasket.

Middle case leaking gasket via the same reasoning as above, if the motor was rebuilt recently or neglected for a while, it may need a retorque to take up the slack.

Best case, worn coolant pipe seeping ever so slightly and running a ring around the seam. Check the heater hoses and the carb heating lines.

 

Keep in mind you will need a torque wrench and a 3/8th drive allen set to retorque the head, can be had for ~20$ for both at harbor freight I believe.

If it is a blown head gasket don't fret too much, you can still do the head gasket job in a day. The worst bit will be taking the manifolds off and making sure you have the chain tensioner installed correctly. 

 

Now that you mention it, a blown head gasket wouldn't be too bad. I have Friday off every week and don't have school until 3 pm, which gives me plenty of time to take care of the maintenance. 

 

I've got a Holley 390 (no carb heating line) and no heat or AC, so there's not really anything to check. I've never done a head gasket (and I've dreaded it in the past due to my inexperience), but I'll get to watching youtube videos and give it a go next weekend if that's the issue. 

 

Thanks a lot everyone for your help and input. 

[Tony D]

"Keep in mind you will need a torque wrench and a 3/8th drive allen set to retorque the head, can be had for ~20$ for both at harbor freight I believe."

 

If you're needing to buy one, buy the correct one: it's 10mm, not 0.375" (unless you like spinning out the flats, then by all means go with the 3/8"!)

 

Ever consider Aluma-Seal and paint?

[Onion]

"Keep in mind you will need a torque wrench and a 3/8th drive allen set to retorque the head, can be had for ~20$ for both at harbor freight I believe."

 

If you're needing to buy one, buy the correct one: it's 10mm, not 0.375" (unless you like spinning out the flats, then by all means go with the 3/8"!)

 

Ever consider Aluma-Seal and paint?

 

You just saved me a huge headache! Thank you!

 

I haven't, there are so many gimmicks on the market that unless I've heard about a product and it's commonly used, I tend not to trust what the label says. I'll look into it, though, thanks again.

 

Also, I did some poking around earlier, discovered this on the other side...

 

 

And then worse...

 

 

I'm trying to find a good deal on a compression test kit since I'm pretty broke at the moment, I'll update once I get some numbers.

[seattlejester]

Sorry for the confusion, I meant a 3/8th drive metric allen set*

 

http://www.harborfreight.com/9-piece-38-and-12-drive-metric-hex-bit-socket-set-67880-html.html

[Xnke]

The issue isn't the initial re-torque of the gasket...it needs to be done regularly. I didn't believe it until it started solving my problems.

[djwarner]

You guys run just straight water in Florida???

 

Actually, I'm running waterless coolant. Made the switch when I swapped my leaking brass radiator for an aluminum one. The waterless coolant won't boil in the hot spots of the engine after shutdown. Never pressurizes the cooling system even on the hottest days running the a/c.