Gurgle/boil/fluid Noises - Video

[No Crust Racing]

Recently replaced the head gasket, head was skimmed, new factory gasket with hylomar (CA18DET).

After driving the car and getting it hot I found it was "gurgling/making a boiling noise from the back of the head more on the intake side.

I jacked the car up and let it run for twenty mins or so and kept squeezing hoses as I assumed it may have air in the lines. It pushed air into the overflow for a while then stopped doing it.

Last night I drove it again after a good warm up and when I came back it wasn't gurgling straight up but started to when I cracked the radiator cap (which also released some fluid into the rag I had there).

It had stopped before I grabbed my camera, but I did record the sound of fluid swishing around coming from the same place each time I squeezed the top radiator hose.

I'm inclined to think the radiator level has dropped, but how much of that was fluid out the cap is unknown.

When I was trying to get the air out, I had the heater on full pelt also and gave the car plenty of revs as well.

My main concern is the headgasket is not sealing. Is the easiest way to check to get a pressure test done? There does not appear to be any oil in the coolant, as there was last time, but the gurgling makes me think that when I shut the car off it's sucking air in somewhere from a leak in the cooling system.

[Shoota_77]

My first guess would be the coolant boiling when you stop due to having no air flow through the radiator.

Did you replace the old fluid with proper anti boil coolant? Proper coolant as opposed to just corrosion inhibitor raises the boiling point of the coolant to prevent it boiling if the cooling system can't keep the temp under 100 degrees c.

It might pay to bleed the coolant from a higher point. Put a funnel or something that will seal in the radiator neck so that you can have the level higher than the radiator. Then open the bleed screw (I presume CA's have them, most Nissans do) and bleed out any additional air. Tighten up the screw while the level is still higher in the funnel than the bleed screw.

If you've got good coolant and it's bled properly then you need to check your radiator to make sure not too many bent fins and not blocked with bugs and crap. Is the radiator old? It may be blocked. Check the thermostat to make sure it's operating correctly (remove it and put it in boiling water to make sure it opens at the right temp (have thermometer in the water).

If everything else looks ok then you might need to have a look at your water pump to make sure the fins aren't corroded. That's a longshot though.

That should give you a few things to try anyway.

Good luck!

[No Crust Racing]

- Coolant is a mix of the old coolant, that was slightly oil contaminated from the headgasket, and fresh water that was put in the radiator to get the car going. I have some radiator cleaner and plans to flush/clean, haven't done it yet while I'm wanting to work out if it's sealed properly.

- CAs dont have a bleed screw, which is why I jacked the car right up so the radiator was the highest point and ran it for twenty mins or so squeezing pipes as I went, air did come out but who knows if it was all of it.

- Radiator is pretty new/in decent condition.

- Thermostat is only 2000ks old and is a high flow unit, it's working properly as the coolant flows as it should when warm.

- The noises come from the back of the engine and I'm semi thinking that the coolant level dropped by some of that came out the cap when I removed it.

- I have an aftermarket gauge and it doesn't go above 77 or so degrees.

I will make some calls at lunch and see what a pressure test costs, I really need to be sure it's sealed.

Edited January 23, 2013 by ActionDan

[Shoota_77]

Ok, that covers most of it then. I would definately flush out the whole system and put in proper coolant before going too much further.

What is the highest point on the engine that carries coolant that you can remove to allow the air out? Using my method from my first post, rasie the fill height of the coolant and remove the hose or whatever is highest to allow any further air to get out.

[No Crust Racing]

It would probably be the top hose which connects to the thermostat housing, that or the radiator cap.

As I mentioned though, I went through that process and my main concern is the drop in coolant level implying it's leaking out or into the engine.

[Shoota_77]

It could be dropping because of the air that is still trapped in the system slowly working it's way out.....

I wouldn't panic yet!

[No Crust Racing]

Haha, not panicked, it's just a track car so it can sit for however long to get fixed. Just don't want to hit the dyno and dial in the new parts if the gasket is not right.

Natrad guy, who was very friendly and helpful, told me pressure test will not help and suggested I'd be better off fully flushing the car then TK testing it, I have access to a TK tester.

I'll keep running/driving the car also, if the level keeps dropping then it's going somewhere, if it's just air escaping then it should level out at some point,.

Edited January 23, 2013 by ActionDan

[No Crust Racing]

I did some more work on it last night with a radiator tester a mate had.

Fouund 3 leaks at 100psi test pressure.

- Top radiator hose which required 2 hoses clamps before I could not hear the air escaping any more.

- Water temp sender adapter which I was able to seal up with a new/better hose clamp.

- 2 lines under the intake manifold next to each other that I'd not tightened up properly.

I made sure they didn't leak up to 140psi on the gauge then let it idle jacked right up for 10 mins before taking it for a belt.

When I got back, the car still gurgled at me, but I got it on video this time. There's a noise halfway through the clip, that's the missus banging around outside the garage water plants.

[No Crust Racing]

Forgot to add, it didn't make any noises in or around that area while I was pressure testing it.

Maybe I should pull the spark plug on 3 and 4 (where the HG was blown last time) and see if I can see/hear anything at the same time.

I'll try and line up a TK tester, but I have to fully flush the cooling system first as this older coolant would still have some oil in it from when the HG went.

[Dobz]

Is the radiator cap new or old?

[No Crust Racing]

"Looks" good, but was on the car when I bought it.

[datsun_1600]

Last night I drove it again after a good warm up and when I came back it wasn't gurgling straight up but started to when I cracked the radiator cap (which also released some fluid into the rag I had there).

The boiling point of water + whatever additive you have in there will change with pressure. The lower the pressure the lower the boiling point. I would fully expect it to make that sound if you crack the rad cap as you have released the pressure from the system. (Remember in science class making water boil at room temperature in a vacuum?)

If the system is not holding pressure it will boil like this. The system will be fine while you are driving and the water temp is low. In fact, you you are just driving along at highway speeds on a coolish day it doesn't even matter if the rad cap falls off. But on a hot day, or when you stop the car and the heat from the block soaks into the water, it relies on pressure to stop it from boiling.

Just my 2c

Jeff

Edited January 24, 2013 by datsun_1600

[No Crust Racing]

Agreed Jeff, but look at the most recent update.

Drove it last night after fixing some leaks and it gurgled without the rad cap being removed.

There definitely could be more leaks, so I will do some more testing.

The big ticket for me was that I could not hear anything in/around the head area or where it was been gurgling. I will flush it all out and get a TK tester on to it, I can deal with it getting some air in or leaking a tiny bit somewhere but I don;t want to put it on the dyno if the head gasket is not sealing.

[Shoota_77]

Is the cooling fan operating correctly? If it's not engaging properly when you stop it won't suck air through the radiator properly to replace the action of the airflow from driving.

The gurgling sound won't be the actual leak, it's the coolant boiling in the block. It may be because there is a leak and as Jeff says, pressure as well as the coolant raises the boiling point of the fluid. But you say you tested up to 100psi so pressure shouldn't be the problem. That's WAY above what a normal system would operate at (from my recollection anyway!).

[No Crust Racing]

Clutch fan seems to be working fine, car doesn't get hot on the factory or after market gauge. It's certainly spinning as expected and I have the shroud in place.

Just get that noise and I thought it may have been using coolant but as I fixed 3 different leaks it's entirely possible that was why.

100psi on the gauge has test next to it, I went 140 after fixing leaks and could hear/see nothing else leaking.

If I let the car idle long enough with the cap removed the coolant level rises to a point where it would start over flowing if I left the cap off which is why I don;'t want to follow a suggestion I was given of driving it with the cap off.

I've jacked it way up twice and let it idle for 15-20mins each time, my jack goes 498mm. I'll get under it and triple check the coolant hoses up under the manifold.

This weekend I should be able to drain everything, flush out the old coolant and put fresh stuff in so I can TK test it without the old stuff in there.

[datsun_1600]

Ah yes - sorry I got busy and wanted to reply. Should have read right through. 140psi ? Wow, I would have thought that would blow the core / welsh plugs out of the block! My very very very modified Datsun L20B engine used to do this, the only way I could stop it was to let it idle for a bit to cool off before shutting it down, and also run fans etc after it was shut off.

I'm currently rebuilding the engine - it now runs an electric pre / post oil pump, electric water pump and fan after it's shut off.

Jeff

Edited January 24, 2013 by datsun_1600

[No Crust Racing]

I'll re-check the tester then maybe it;s not psi and in fact something else. It's definitely 100 somethings.

At 100 (whatever the unit is if its not psi) the radiator hoses are almost rock hard to touch, they were not anywhere near that hard after driving it and keeping the cap on while it was hot and pressurised.

[datsun_1600]

100 KPa = 14.49PSI would make sense.

Edited January 24, 2013 by datsun_1600

[No Crust Racing]

After looking at the pic I posted again in more detail you are right, the PSI is on the outside of the measurement ring, which shows 15-20-25 etc against it.

[datsun_1600]

I'll re-check the tester then maybe it;s not psi and in fact something else. It's definitely 100 somethings.

At 100 (whatever the unit is if its not psi) the radiator hoses are almost rock hard to touch, they were not anywhere near that hard after driving it and keeping the cap on while it was hot and pressurised.

Interesting.... Wonder why it's not building pressure in the system when you drive it.....