2000 V70 AWD 56 engine coolant now 1 in. higher in reservoir

[850oldschool]

From time to time I'll drop in here and mention that my coolant level is much steadier since I replaced the cap on my car. The rubber sealing washer broke in two pieces quite easily on the old one.

Carry on.

[Rocket99]

Quick math

Expansion bottle is about 10x10 cm, so each cm of change represents 100 cm^3 of volume

Total system volume is 7 liters or 7000 cm^3

so an inch of change is 250 ml or about 3% expansion of fluid volume.

Thank you ....
love it when logic gets involved
Starting from scratch again on this story: checking coolant level cold then full heat recenty every day: tiny change usually with driving / checking daily now to figure this out
month ago or so, a short time ago (after not checking it for two months or so) it was an inch below max so I refilled to max, assuming a small leak , losing that inch slowly over the 2+ months I wasn't checking.
Immediately after that top up, first trip, the coolant was 1+ inch above max. Freak out: I've replaced on engine already due to cooling issues,. Block leak detector fluid remained blue indicating no head leak.

jacked it up in front, went under with flashlight and did not see any evidence of coolant leaking

IN spite of all the wise experienced generous feedback I still have no satisfactory understanding of those events.

[scot850]

I have a 03 Toyota 4Runner V8. The header bottle when cold is almost completely empty at the MIN mark. I filled up to MAX and it leaked out when hot. Dealer told me not to fill up as system needs room to expand and that the level is normal.

Volvo P80's are the same.

Neil.

[Sveedy]

I'd say most importantly where is the level now ? Has it stabilized or is it continuing to vary up and down ?
If it's stable, then I wouldn't worry about it. Just keep an eye on it to see if it does it again. Mine doesn't move more than 1/2" or so hot to cold.

[Rocket99]

Thx Sveed i agree around town I'm not worried and would just watch it, . It is stabilized now. I'm a science type and I need to account for the crazy ness of what it did especially siince it "ate" one engine already. It was just after I got the car and that is hangin around like a childhood trauma ACE adverse childhood events.

Also, I will be driving SF to San Diego most of that is middle of nowhere plus or minus and I'm in a burn out state going for cancer treatment so I'm not up for a sudden obstacle along the way now.

[Rocket99]

I have a 03 Toyota 4Runner V8. The header bottle when cold is almost completely empty at the MIN mark. I filled up to MAX and it leaked out when hot. Dealer told me not to fill up as system needs room to expand and that the level is normal.

Volvo P80's are the same.

Neil.

Since this ordinarily is stable level little change between cold and hot. Before I can trust it on a road trip I'll need to understand what it is doing.

Its a hangup

[rguzz]

Heater core can be subtle source for loss without obvious leaks. Mine just smelled a bit, residue around the fins, and very slow reservoir leak. I drove it for a year, everywhere, like that. As has been suggested, it would be reasonable to take a relaxed approach for a bit. When the problem declares itself, science will explain it. At least it appears not to be your HG.