Is there an acceptable amount of coolant loss a vehicle will have over time? I have never really monitored coolant loss until the last few years when I had a lower intake manifold leak. I got that leak repaired about 3k miles ago ( I think) but I notice I have lost about 1/2 cup of coolant over 2600 miles. Car runs fine temps are fine and no visible external leaks or smoke during start up. I will continue to monitor to get a baseline before I decide if I want to do anything.

I've owned my 4runner since 2003 and currently has 280k

I have a v6 with 5speed and radiator is somewhat new.

Seeking out any advice

Thanks

MikeM

It wouldn't hurt to do the gaskets as I suspect they're probably the culprit personally. When I did my intake manifold gaskets ALSO around 280k (as part of solving a different issue) I noticed the material around both coolant passages on both gaskets was heavily eaten away, as in if I had left it for another year I probably would've been leaking into one of my intake valves - they were all holding on by a hair. Given both the age and mileage our vehicles are approaching I wouldn't put it past things if you have the same issue. And considering you can buy the gaskets online fairly cheap and it's not exactly a complex job (just tedious, especially by yourself) I would give it a whirl and see if it changes anything. I went with felpro instead of Denso as they were much cheaper and have absolutely nothing bad to say
Worst case scenario it was a few bills and an afternoon down the drain but at least you can rule it out at that point

Thanks for reply but I have already replaced the lower intake manifold gaskets. I should add the bypass and valley were dry. Water pump was dry and sparks plugs looked fine.

Thanks

MikeM

How are you determining that the coolant loss?

Wouldnt hurt to test the cap for the correct psi. I believe its rated 15.6 psi. You can rent one from loan a tool program at the big block auto stores.

you say you did the lower intake gaskets 3000 miles ago and since have lost 1/2 cup of coolant.....was it all of a sudden ? did you just now noitice and have not really paid attention to it since the intake manifold gaskets ? Maybe it just needed to burp an air pocket.
I had a 2001 for a brief time, it would loose coolant...part of its issue is previous owner had installed wrong radiator cap

I have been checking coolant level in the morning and right after I had gaskets replaced I was checking it daily. I'd say the first couple thousand miles I didn't see a drop in coolant and didn't check it for awhile and lately notice it was about 3/8 below the full line when engine is cold. I'll continue to monitor it and see if it drops any further over time.

I might pressure test it as well

Thanks

MikeM

Been there, done that on multiple Toyotas. A new OEM cap fixed it.

Not saying that is the issue in this case, but also worth checking.

-Charlie

I did by a spare cap and can try it to see. My current cap I replaced over 100k miles ago so I supposed it could be due. Doesn't hurt to try since I already have one

Thanks

MikeM

You can get some UV dye and glasses. If the leak is external this should help you locate it.