Cracked block?

Post by **Ludermilch** » 30 Sep 2019, 16:42

Hi all MVS members,

Am I correct in thinking that this is a cracked block? Lots of coolant loss caused me to assume that it blew a gasket then found this under the intake manifold.

Thank you for your time and expertise.

Post by **abscate** » 30 Sep 2019, 17:37

Yes, looks cracked starting at’ the coolant stain. Might be able to JB weld it to get some more life out of it.

Post by **scot850** » 01 Oct 2019, 00:11

Certainly not a common problem. It looks like a crack like abscate says. I would clean off the front of the block where the stain starts at the top. You may be able to get a dye to highlight if there is a crack.

Is the radiator good in front of where the rust is and the radiator hoses?

Neil.

Post by **abscate** » 01 Oct 2019, 03:38

Closeup,

Post by **Ludermilch** » 01 Oct 2019, 08:11

scot850 wrote: 01 Oct 2019, 00:11 Certainly not a common problem. It looks like a crack like abscate says. I would clean off the front of the block where the stain starts at the top. You may be able to get a dye to highlight if there is a crack.

Is the radiator good in front of where the rust is and the radiator hoses?

Neil.

Thank you Neil, Abscate. Conclusion is that it is indeed a crack in the center of the block. Radiator and hoses check out. My next step is to do a weekend motor swap with the motor I have in the garage.

Onto the next adventure.

Post by **jimmy57** » 01 Oct 2019, 08:40

That is block rot cracking. It is what happens when nasty stuff sits in the bottom of aluminum and electrlysis starts and eats throgu hthe aluminum. The rust in the leaking water feeds electrolysis.If you stick dc voltemter leads in coolant tank touching the coolant and then touch block you will likely see over 250 mV (.25V)

Post by **Clemens** » 01 Oct 2019, 15:15

what can one do to prevent this? flush the coolant?

Post by **misha** » 01 Oct 2019, 16:10

Clemens wrote: 01 Oct 2019, 15:15 what can one do to prevent this? flush the coolant?

I would say that regular coolant change will prevent this.
I'm changing coolant every 3-4 years and the old one looks like new....without a hint of corrosion in the system.
Most people doesn't know that coolant becomes agressive when it's not changed regularly.
It protects cooling system and block for 2-4 years or specific mileage(depending of coolant type) but afterwards it becomes agressive and slowly starts eating cooling system and block.

Also different types of coolant must not be mixed.I don't even mix the same type of coolant with different brand.

Only destilled(demineralized) water must be used for mixing with coolant.Mixing with tap water can cause something like this...or worse....using JUST water instead of coolant.

Post by **jimmy57** » 01 Oct 2019, 17:12

It is rare on Volvos in my experience to see nasty coolant. The cooling system has little different metals but the water pump is plated steel and will lose plating if the coolant gets bad. Volvo used long life coolants since about the time the 960 came out and they dropped regular coolant changes. Their wording was something to the effect of replace coolant whenever cooling system components are serviced. Hoses got better as did water pumps and radiators (yes, compared to 4 year life on ones in late 80's to mid 90's) and I think minor loss and adding other than distilled water may have caused some nasty things with coolant that allows water pump impeller to rust. Anyway, flushing and changing coolant every 5 years with good long life modern coolant would probably stop anything ugly from happening.