Running hot

1962-1965 Datsun L320 and NL320 forums - The truck that started it all in the US. All 320-specific topics and discussion can be found here.
Gemmer
Posts: 90
Joined: Mon Jan 27, 2014 5:38 pm
Car: 1964 Datsun PU 320
Location: Roseville,Ca

Running hot

Postby Gemmer » Thu Aug 14, 2014 12:36 pm

Got my 64 running but it is overheating quickly. Drained the radiator but can't get the drain at the block to drain ( tried blowing compressed air back through but that didn't work either also attempted to run a wire back through but no joy ). Pulled the thermostat ( checked to see if it opens, which it does ) reassembled with out the thermostat. When I rev the engine I can see water moving at the filler. This suggests to me the pump is working and moving water. I guess the last thing I can do is an aggressive flush. If that doesn't work, looks like I'll have to pull the water pump. Any other suggestions are welcome.


DylanFM
Posts: 15
Joined: Sun Apr 13, 2014 1:20 am
Car: NL320

Re: Running hot

Postby DylanFM » Thu Aug 14, 2014 10:00 pm

Might be a stupid question, but how do you know it is running hot?

The reason I ask is that my '65 NL320 had been converted from positive to negative ground. Everything works except the temperature gauge reads backwards. When it is cold it reads pegged hot and then moves closer to the 'C' as it warms up.

If you are using the stock gauge and/or sending unit I'm not sure I would trust it regardless if was converted from positive ground or not. I would try to verify that it was really overheating before tearing anything apart.

Gemmer
Posts: 90
Joined: Mon Jan 27, 2014 5:38 pm
Car: 1964 Datsun PU 320
Location: Roseville,Ca

Re: Running hot

Postby Gemmer » Thu Aug 14, 2014 10:09 pm

Dylan,
Not a stupid question at all. My temp gauge is working properly. Additionally I have checked with an external temperature gauge with a probe I can stick into the open fill at the radiator. Climbs up to 210 degrees then I shut the engine down.

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Li'l Truckie
Posts: 554
Joined: Thu Jan 02, 2014 9:28 am
Car: 3 x '65 PL 320
1 x '64 PL 320
1 x '63 PL 320
1 x '62 PL 320 - parts :(
1 x '60 PLG-222
and many more Datsuns from 48hp to over 500hp
Location: Leavenworth, KS

Re: Running hot

Postby Li'l Truckie » Fri Aug 15, 2014 5:15 am

Gemmer,

As far as the over heating goes, first thing is to check the thermostat. Its probably not working and is stuck closed or barely opening.

Here's what I think might be wrong (done this myself) - You might have overfilled the radiator, up to the neck. And since there is no room for expansion the antifreeze gets hot and boils over. Since it is boiling out the neck it is not properly cooling the cylinder head or block.

As far as the thermostat working "congrats" on a working gauge! I don't think any of mine work, they are either stuck at the bottom or top. I think one might go from the bottom and pegs out at the top once at running temp, but I know it not overheating.


Other issues that might cause it to run hot, but not really overheat -

-Dirty/clog radiator - boil it out or from Greg get water hot and run some vinegar through the system

-Over filled radiator - anti-freeze should just cover the top of the cooling tubes - should NOT be filled all the way up to the neck of the radiator. The Nihon radiator is vertical and not the better designed horizontal/cross flow type radiator.

-Water pump going bad - should just leak out the weep hole and not really over heat - fan blade is turning right? if not...

-Belt tension - might be too loose and slipping or generator and/or water pump are going bad and not letting the belt turn...do you smell burning rubber?

-Anti-freeze it not diluted properly.

Okay, you probably know all of this, and again, the above might cause it to get hot, but not necessarily overheat. So if you are a GO and have no issue as listed above, I'm kind of at a loss. The E1 is a durable engine where oil and anti-freeze are optional.

I'm working on Shroom, '64, and getting the tool boxes ready to go get my '65 at my parents, so I'll be checking in. Just let me know if you any further issues.

Andy

Gemmer
Posts: 90
Joined: Mon Jan 27, 2014 5:38 pm
Car: 1964 Datsun PU 320
Location: Roseville,Ca

Re: Running hot

Postby Gemmer » Fri Aug 15, 2014 4:03 pm

Thanks for the suggestions.
Am currently doing a 3 day deep flush with "Prestone Radiator Flush"
Question, what does distilled water and vinegar do that the Prestone product won't?
I did in fact have the radiator filled up to the neck, changed that.
Had also forgotten that a water/anti-freeze mixture runs cooler.
I'll let you know how this works out.

User avatar
Li'l Truckie
Posts: 554
Joined: Thu Jan 02, 2014 9:28 am
Car: 3 x '65 PL 320
1 x '64 PL 320
1 x '63 PL 320
1 x '62 PL 320 - parts :(
1 x '60 PLG-222
and many more Datsuns from 48hp to over 500hp
Location: Leavenworth, KS

Re: Running hot

Postby Li'l Truckie » Fri Aug 15, 2014 4:08 pm

The Prestone should be fine. Its just a little more expensive than the white vinegar.
Andy

Gemmer
Posts: 90
Joined: Mon Jan 27, 2014 5:38 pm
Car: 1964 Datsun PU 320
Location: Roseville,Ca

Re: Running hot

Postby Gemmer » Sat Sep 06, 2014 10:40 am

Well it has been more than a couple of days, the 3day flush did not help so I took the radiator in to a local radiator shop and asked them to flush it out. They called me the next day and said it was so clogged that a rod out was the only way to fix my problem. I'm not a very trusting soul when it comes to auto repair shops so I asked them to show me the core once it was exposed. They agreed and short story is they were absolutely correct. Really clogged. Who would have thought, only 50 years! Back in the truck now and all is good!

User avatar
Li'l Truckie
Posts: 554
Joined: Thu Jan 02, 2014 9:28 am
Car: 3 x '65 PL 320
1 x '64 PL 320
1 x '63 PL 320
1 x '62 PL 320 - parts :(
1 x '60 PLG-222
and many more Datsuns from 48hp to over 500hp
Location: Leavenworth, KS

Re: Running hot

Postby Li'l Truckie » Sat Sep 06, 2014 5:49 pm

Gemmer,

Sounds great! Rust from the engine will do that, especially after 50 years of operation and from just sitting. Hope it's running a lot cooler now.

Li'l Truckie


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