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Gurgling at Shutdown from Heater Core

Kaajot

Micro Machine Manager
Next weird thing. Truck has no check engine light, things are going well but I think I'm eating gas still. Engine likes to rev up when at a stop in gear, really odd.

Anyway, issue I'm asking about is the Heater Core is gurgling and evacuating itself very loudly at shut down.

Is this normal?

I know I've owned the truck since 2009, but pretty hyper sensitive at this point as we break in this new engine at 500 miles (oil change tomorrow).

Heater Core was replaced (probably unnecessarily, was likely a bad thermostat and water pump issue, also both replaced) in 2018 or early 2019.
 

Blue-Truck-Nut97

crank polisher
551
18
I've had some do that over the years. No real reason I found. A couple suggestions, check your coolant strength, too weak means a low freeze point, as well as a low boiling point, next item would be the pressure radiator cap. If the system isn't pressurised, the coolant can boil.

A few items to consider

What is the coolant temp when it does this?

Are you running the A/C?

Does it do it constantly or on certain occasions?

Sent from my E6810 using Tapatalk
 

CowboyBilly9Mile

Charter Member
7,118
444
USA
What does the mechanic at the shop say is causing this?
 

Kaajot

Micro Machine Manager
What does the mechanic at the shop say is causing this?

I haven't put it to him, we're working on a Saab right now and have more pressing issues. You wanna phone him?
 

Kaajot

Micro Machine Manager
I've had some do that over the years. No real reason I found. A couple suggestions, check your coolant strength, too weak means a low freeze point, as well as a low boiling point, next item would be the pressure radiator cap. If the system isn't pressurised, the coolant can boil.

A few items to consider

What is the coolant temp when it does this?

Are you running the A/C?

Does it do it constantly or on certain occasions?

Sent from my E6810 using Tapatalk

The coolant could be light on antifreeze and more water. Will have to test percentage, know Keith has a tool for that in his shop.

Temp is staying fairly cool, doesn't give me a number, I've just got the C-H temp dial. It often stays in the C range, but if I stay idling for 20 mins while working at my farm (taking care of chickens) it'll get about a third up the gauge.

I think the radiator cap could be a little damaged, but it does hold at least some pressure and has the depressurization toggle on top to open and relieve pressure. Have used recently, but before that when the old engine was in it this Summer, it blew off once or twice so it could be faulty.

I don't recall it gurgling tonight, but I didn't stay idling for 5-15 minutes in the drive way like I often do while on the phone.

Do not have Air Conditioning, but I also was not running heat tonight so again, there's that.

I think the stock temp is 195 thermostat, but I am running a 180 and was considering going to a 165. Should I go back to a 195 being in the North? It does appear to be functioning -- temperature climbs up, thermostat opens, C-H temperature gauge moves, warm air comes out of heater core into ducts.
 

CowboyBilly9Mile

Charter Member
7,118
444
USA
I haven't put it to him, we're working on a Saab right now and have more pressing issues. You wanna phone him?

Thanks, but no need. Any vehicle work ever needed here is done by an experienced owner that can get it done right the first time. On the rare occasion that special tools/equipment are required, the job is farmed out to a qualified, experienced, demonstrated and proven professional who understands that customer satisfaction is paramount, and who values their reputation in the community.
 

Kaajot

Micro Machine Manager
Thanks, but no need. Any vehicle work ever needed here is done by an experienced owner that can get it done right the first time. On the rare occasion that special tools/equipment are required, the job is farmed out to a qualified, experienced, demonstrated and proven professional who understands that customer satisfaction is paramount, and who values their reputation in the community.

Sound like you got it all worked out.

Also, you don't need to reply to me anymore.

It's obvious how much you want to not be a :nana:
 

CowboyBilly9Mile

Charter Member
7,118
444
USA
^^ To the contrary, we all enjoy reading about your successes when they happen, do keep them coming!!
 

Fellro

Moderator
Staff member
It would also be worth verifying the coolant level is full as well. Tiu should not have nay headspace in the radiator. The heater core is thehighest point, so also the first to show low levels.

On the speeding up at idle, I had that happen on my 88, actually would get to racing pretty good, over 2000 rpm. The throttle position sensor was bad. I was putting up snow fence and it was just revving away because I left it idle since I was working by the headlights. Sometimes would respond to bumping the throttle, but then would just climb back on its own. Vacuum leaks are another way that can happen.
 

Kaajot

Micro Machine Manager
It would also be worth verifying the coolant level is full as well. Tiu should not have nay headspace in the radiator. The heater core is thehighest point, so also the first to show low levels.

On the speeding up at idle, I had that happen on my 88, actually would get to racing pretty good, over 2000 rpm. The throttle position sensor was bad. I was putting up snow fence and it was just revving away because I left it idle since I was working by the headlights. Sometimes would respond to bumping the throttle, but then would just climb back on its own. Vacuum leaks are another way that can happen.

Appreciate it. Yeah, I'm theorizing based on my research there's a pinhole leak in the antifreeze system. Mechanic of course says if there was, we'd see fluid, but viscosity and surface tension are factors he won't take into account. Air could come in after shut down from such a small pin hole without leaking the fluid. I'll work on tracking it down later, but am working on the vacuum/idle first.

I tried pulling the IAC connection off, no change at all in idle. I still have to do what dusty suggest and take a look at it, the pintle (sp?) and carb up, gasket's condition for a vac leak, etc.

Watched a ScannerDanner YouTube vid about the entire thing with Fords, and unless the mechanic fixed the Throttle Body adjustment once the new engine was in, I'm 99% certain it's set to a very high RPM and may be the 100% cause. Going to disconnect the PCM communication (wiring bundle) off the IAC, run the truck, and back the throttle adjustment off to get to 400-500 low idle and then reconnect the IAC. It should, if working, create an immediate change in idle that it does not at the moment because PCM will be able to communicate and control within tolerances again.

TPS is a good thought, we replaced TPS and the MAP during the engine install as both had been abused by the rough oil-leaking engine this Summer (mainly by throttle being set too high, oil of course secondarily eating away at all things rubber to include wiring bundles).

Everything is out of tolerances if the throttle body adjustment screw is rev'd way up, which was a temp fix we used for the engine when it was running poorly and I was leaning towards a rebuild or new engine. New engine of course won and both of my blocks are headed to scap yard on Monday along with my saab shell.
 
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Kaajot

Micro Machine Manager
^^ To the contrary, we all enjoy reading about your successes when they happen, do keep them coming!!

Which successes made your day over the last 4 years? 'drama'

I need to document them for my AUTO biography. smilieneenar

The F-700 on the road again repairs and police escort was probably my greatest solo release in 2019 It ranked Top 40 Honky Tonk Blues for a week in Georgia. 'badachang'
 
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