Cavitation

[RNSF]

So, recently I removed the blower and did an HCI swap and have been having some cooling issues that I have never dealt with before. At first The car would run hot and puke coolant on shutdown every time loosing about a gallon or more each time, this was solved by simply changing the bad radiator cap. Now I have a new problem, even though it was already there, it has just become more apparent now. I took it around the block a few times and had a much better temperature and the thermostat seemed to be opening correctly. I parked it and then popped the hood to find that the overflow tank was violently bubbling again, just not puking this time. I relieved the pressure, removed the cap and started it again to check for flow and noticed that the once full rad was over half empty. The coolant was flowing through the tubes but in spurts while coolant was erupting from the bottom of the rad, no foaming was observed, no bubbles in the coolant, no smoking of the exhaust.

When the cam was changed, I reused the old water pump and plate, I cleaned all the surfaces throughly, I did notice that the plate had a fair amount of pitting, all gaskets were RTVed for good measure.

So this one is new to me, either I have a nasty cavitation issue or something more serious. Thoughts? Experiences?

Aluminum heads, GT40 lower, 180deg MG stat, Stock rad, old pump, new gaskets, new cap.

[Outlaw86'd]

boom

[RNSF]

boom

No exhaust smoke, no sweet burning coolant smell, not over heating. Just lots and lots of pressure and mysterious vanishing coolant.

[Outlaw86'd]

bang

[RNSF]

bang

Ill give you a bang

[iamtheshaner]

Compression gasses for 500 Alex

[RNSF]

Compression gasses for 500 Alex

I was thinking that, but If that was the case, where did over a gallon of coolant disappear to in 2 miles? Its not in the exhaust. From what I observed, its unlikely.

[5.0stang85]

you need to bleed the system of air

one way of trying to do it is jack the drivers side of the car up on to a jack stand about 14"-16" off the ground AND only the drivers side

start up the car with the rad cap off here is where you'll need someone to help on a EFI car

have someone rev the motor repeatedly from idle to 3,500-4,000rpms and you watch the coolant in the rad and the temp gauge and don't add any unless you need to... just make sure to do that up to operating temp

I did this on my 83 for 20 minutes and it got 85% of the bubbles out

also make sure your reservoir is full as it will help bleed air to hook that up

if this don't work I'll come out this weekend if you're free and help if it's not raining

[YouNeverSawMeHere]

bubbling is normal when hot and right when you shut it off...
the coolant that sits in the block boils until it cools down.

Bubbling while it's running... very bad. You can take it over to north oaks auto service off centerville road for an exhaust test on the coolant system... the guy only charged me $40 to do it... but it was a saturday and I paid in cash.

good luck

+ Should have burped the block after you got it together... while holding the throttle open to 1/3 with your right hand, fill with the left hand to the top off the radiator, then throw the cap on quick. Let go of the throttle. The excess should go into the overflow if you have it plumbed correctly. With the release of the throttle there should also be enough pressure to push the excess into your overflow.

Within 6 hot to cool down cycles the system should have no pockets of air anyways... just do not vent the cap while its cooling down or you will have more pockets... when you restart the car it will pull the coolant that was pushed out when it was hot back in.

unless you have a blockage I don't think cavitation is an issue here.

[bluchev]

Compression gasses for 500 Alex

This.

sounds like the headgaskets (that you probably re-used) are leaking.

[bluchev]

you need to bleed the system of air

one way of trying to do it is jack the drivers side of the car up on to a jack stand about 14"-16" off the ground AND only the drivers side

start up the car with the rad cap off here is where you'll need someone to help on a EFI car

have someone rev the motor repeatedly from idle to 3,500-4,000rpms and you watch the coolant in the rad and the temp gauge and don't add any unless you need to... just make sure to do that up to operating temp

I did this on my 83 for 20 minutes and it got 85% of the bubbles out

also make sure your reservoir is full as it will help bleed air to hook that up

if this don't work I'll come out this weekend if you're free and help if it's not raining

:idiot:

[5.0stang85]

:idiot:

um no if the head gaskets are good then my way will work see in fox mustangs the rad cap is on the drivers side tank at about a 45* angle and to properly bleed the system you need to make the cap opening the highest point to bleed the air out

other wise with the car level on the ground and the cap off all you'll do is suck air in the system trust me I just went threw this on my 83 it will look sketchy but it works

[Slow35th]

inb4 legoguy...err wait.

[Macs Stang]

Could be the intake gaskets as well. When I first installed a TFS intake on my car years ago I didn't align the intake gaskets with the tabs on the head gasket, which caused the system to have a leak. Well after running I could hear the coolant boiling in the overflow. Put new gaskets in and it worked perfect. Could be that since you said you just swapped intakes.

[TRDon]

do you have a pinhole (1/16" or so does it) drilled in your outer edge of the thermostat? If not you should, it will help it burp. I would tell you to jack the car up as high as you can on one side and rev it to 8k, but that would be retarded. Have a hole in the stat, fill radiator, take off upper hose and fill coolant at the stat housing until it doesnt go lower. I never had to burp anything doing it this way, it will burp itself as it fills.