Blown HG or worse?

[Matt H]

Hi everyone,

I should probably start by saying this is my first post. I'm also starting at the very beginning when it comes to working on cars so please be patient with me. After 2 years of looking my partner and I finally decided to purchase our first classic car. Our car of choice was a 1971 Datsun 521 1600 L16 Pickup. We did our best job at trying to get as much info on the vehicle as possible before we made the purchase however it appears there were a few things that we clearly missed. After looking at some of the posts on Ratsun I suspect i'm dealing with a blown head gasket and or valve gasket. The previous owner told me the car has an oil leak which needs topping up from time to time but from what I can see I suspect there may be oil in the radiator / coolant and potentially coolant in the engine as I see a green residue on the exterior around the bottom of the engine bock.

I've attached some pictures below. There is visible oil on the passenger side of the engine that appears to be coming from somewhere around the headgasket , valve gasket and maybe oil filter. You'll see from the images it follows the seam of the engine. I've also noticed leaking oil around the underside of the vehicle. The oil doesn't leak a huge amount. Literally just a couple of drips over the last few of days. However I suspect it leaks more when the engine is hot. My partner also said that when I arrived home after picking up the vehicle and driving it 30 mins a noticeable amount of smoke came from the exhaust when I switched the engine off. 

 

I've checked inside the oil cap and their is no 'choc milkshake' inside the engine head. It actually looks super clean. But the radiator coolant definitely looks a little off. I would really appreciate your help in identifying the possible cause. 

Thanks,
Matt

 

 

 

  

 

 

 

 

[datzenmike]

Matt, welcome to Ratsun. The 521 is well liked and represented here. I had a 5 or 6 year old '71 back in the day for about 8 years.

 

 

This is classic valve cover gasket leaking. Rather than just tighten, and have that not work, I would replace it and snug the bolts down wrist tight to start. Now take to the car wash, the ones with the wands like a power wash and clean everything. Perhaps get a bottle of that citrus de-greaser and spray down everything first. Don't spray directly at the distributor. Later when everything has dried, watch for emerging oil. If at the valve cover carefully snug the closest bolts.

 

A blown head gasket never presents with oil leaking....

It can blow clouds of steam out the exhaust in combination with constant coolant loss. The steam can by pass the rings and mix with the oil turning it a milky coffee brown.

It may always over heat

One or more spark plugs may be suspiciously cleaner than the others.

 

 

Get some rain gear on and power wash all that black crap off. It may take multiple trips to the car wash to get it all but take your time. Once cleaned it will stay clean if it was only the valve cover gasket. If you find any more leaks we''ll deal with this later.

 

 

This is fine!!! Needs a proper 50/50 mix of coolant/anti freeze though, to reduce corrosion. Never use or top with tap water... buy a gallon of distilled water.

 

 

 

[banzai510(hainz)]

I use a pressure washer but one has to be carefu;l not to blow all the motor paint off and get the dist cap wet and alternator /starter directly wet

 

I sprsay with engline cleaner and let sit then blow it off.

carfull of the fuse box also getting wet. 521 have alot of proplems with corrssion in this area where lights dont work , but simple fix.

 

th dist look like it off 180deg from stock where the vac adv is but if works there dont fuck with it untill you know more about cars.

Maybe Ike know since the dist is 180 off the bigger cap should be the main points but I see a blk/ yellow which is the 2ndary set I think.

 

does this run fine right now?

Edited October 18, 2021 by banzai510(hainz)

[Matt H]

Thanks for the prompt and detailed reply both! I'm so glad I found this forum...

Ordering the new gasket now. Should I use any silicone / weather stripping glue to secure it?

I see the previous owner has receipts for a new valve gasket from just last year but perhaps it went again...

The clutch is starting to slip in 1st but other than that the engine and car is pretty solid and runs well. 

Will keep you posted!

Cheers!





 

[datzenmike]

Perhaps a cheap cork type and just needs a slight tightening. They tend to compress and need to be snugged. Never use sealer on a gasket. Sealing is what the gasket is designed to do. Eventually you will want to take the valve cover off and if it's glued on it will...

 

a/ probably tear the gasket that can be re-used.

b/ is a pain in the ass to clean head and valve cover to put a new one on.

 

If cork lightly wet the gasket surfaces with engine oil and install.

 

 

 

That's a lot of oil under the car. Maybe the oil pan gasket is also leaking or maybe the engine rear seal. I suppose some of that oil may get on the clutch disc and cause it to slip.

 

Clean the engine and see where the wetness is.

[Matt H]

Thanks Mike! 

[banzai510(hainz)]

I buy the Felpro valve cover gasket the black on you car reuse it .

key is gently tighten it even all the way around then stop. and drive it

 

as for the clutch one can adjust the slave cylinder under the trans , the clutch fork. there is a half moon nut with a lock nut. 12mm I think and this needs to be adjusted. Hopefully the guy sold you this cheap otherwise he should have told you all the issues with this

 

Really Im hoping you 2 are mechanic oriented otherwise this truck will take up your time and money, maybe you  should have not gotten this a 510 woud have been a EZer to maintain vehicle. Changin a clutch is a pain in a 521. I do it by pulling the motor as it EZer for me .

 

as for the oil under the truck the rear trans seal might be the issue . I have this proplem also and swap the seal twice and still leaks. I just make sure I top off every 2 months.I said fuck it as it hard to get that seal and tire of pulling the drive line out and loosen the center driveline bearing

[Matt H]

Thanks banzai510!

 

[Matt H]

Hi Mike / Hainz

I was wondering if you knew where I might be able to find a replacement transmission input and output seals for my 521? Are they quite hard to find? Are they similar to the ones for the 510?
 

[datzenmike]

Front seal 32113-N2101.... used on the 521/510, 610, 710, B-210 (5 speed only), '73 620 with L16 engine, '77-'79 S10 200sx 5 speeds, '78-'81 A10 HL510 4 and 5 speeds. 

 

Rear seal 32136-E0100... used on all Z car 4 speeds and Roadsters, 510/521/620, 610, 710

 

NAPA or any auto supply should be able to get them.

[Matt H]

Thanks Mike - super helpful! 🙌


 

[banzai510(hainz)]

if it not leaking alot I would just park in the gvravel

the front seal of the transyou have to pull the cover. the rear is doable but still a pain in the ass. I have done it twice. If a slow leak I would not worry. But if you have OCD on oil leaks one should not have gotten this truck.

 

get the seal that has 2 lips. I got a SKF brand it only has one lip. thing leaked not long after I installed it.

also there is a gasket there also when the plate for the seal comes out but soem say just use selant as that gasket might not be avail

 

you jave to loosen the carrier bearing up also when you pull the driveline out of the way

 

remember Datsun 521 the body is SAE size threads the motor is metric so do not mismatched bolts

Edited November 22, 2021 by banzai510(hainz)

[Matt H]

Hi Mike / Hainz,

So I ended replacing the clutch including the transmission input and output seals and a bunch of other stuff. It also looks like its finally stopped leaking oil which is great. However, I was pretty disappointed to see the clutch was still slipping again even after the new clutch kit. It's not as bad as it was but I feel like it will potentially wear out again. It's really only noticeable on hill starts or if I give it a moderate amount of gas pulling away in 1st or sometimes 2nd. If I baby the clutch I can pretty much avoid it 95% of the time. It's just frustrating more than anything. Any ideas of what might be causing it to slip?

[jagman]

When you removed the clutch was the flywheel oily?  

[datzenmike]

7 hours ago, Matt H said:

Hi Mike / Hainz,

So I ended replacing the clutch including the transmission input and output seals and a bunch of other stuff. It also looks like its finally stopped leaking oil which is great. However, I was pretty disappointed to see the clutch was still slipping again even after the new clutch kit. It's not as bad as it was but I feel like it will potentially wear out again. It's really only noticeable on hill starts or if I give it a moderate amount of gas pulling away in 1st or sometimes 2nd. If I baby the clutch I can pretty much avoid it 95% of the time. It's just frustrating more than anything. Any ideas of what might be causing it to slip?

 

Do you have about 1/16 to 1/8" of loose play between the clutch arm and the push rod?

[banzai510(hainz)]

12 minutes ago, datzenmike said:

Do you have about 1/16 to 1/8" of loose play between the clutch arm and the push rod?

this and was the flywheel nice and flat or was it like your 1980s Ronco disco hits of the 70s record????

 

maybe  did your kit have a T/O bearing?  and you used your orginal to sleeve. otherwise  you need to adjust the arm at the fork arm. adjust that half moon ball and jam nut at the clutch fork arm so there is a little slop.

 

take photos  maybe a different slave from a newer datsun was instaledd and the rod length is wrong?

 

look like it di this task for nothing if it truely is bad best not to rush in to this and get multiple opinions

 

is this motor actually a L16?

4 speed trans?

what was the clutch kit? number?

Edited November 23, 2021 by banzai510(hainz)

[datzenmike]

This above... push rod play is critical for proper clutch engagement. 

 

 

 

[banzai510(hainz)]

also was the clutch master swap recently?

make sure it not pushing prematurely but the bottom must be 1/16 inch slop in the rod then you know the clutch fork is fully forward.

[datzenmike]

Old clutch slipped.

New clutch slips...

 

Maybe not the clutch. Perhaps it's the perception that it's the clutch slipping. Exactly what happens? Does the engine rev up with the clutch pedal fully up, but the truck does not accelerate????

 

 

 

Could be the old oil wasn't completely removed from flywheel or the cause of the oil leaking isn't fixed.

[banzai510(hainz)]

I got a input seal leaking or the gasket as I know it trans oil but my clutch dont slip