Hi All, I've had an annoying coolant leak for a little while that I can't seem to figure out. The overflow tank will slowly go down little by little after drives. I have filled it several times so it doesn't go dry. I never see any liquid on the ground or in the engine bay. I added some uv dye and looked carefully with a uv light after my last drive a coyple days ago. I took many pics and a video afterwards. Looks like it has sprayed in many places so it's hard to determine the source. Hopefully the images show the uv fluid clearly enough. I also took a video buts mp4 so it won't load. Maybe someone can see something I'm missing to nail this leak source. Any insight is much appreciated.

 

Pressure test it.

 

if I'm interpreting those pictures correctly it looks like it has gone everywhere. I've heard of waterpumps leaking and the pulley spinning the coolant about the engine bay which may be the culprit

Agree pressure testing is useful and not expensive

do you see bubbles in the overflow tank when running? Any major coolant work in recent times? I had air trapped in my new vortec engine for awhile and took quite a bit of burping the system to get it all out - in the meantime the coolant level was going down (whilst air was being replaced with coolant)

 

Thanks for the feedback. I did pressure test it prior to adding the uv dye and discovered that a capped low coolant level port on my Dewitt's radiator was leaking. I tightened it and retested and pressure was holding so I thought it was ok. Then more leaking so I did the dye. Good suggestion and I will pressure test it again. It does seem like it's splattered all over. I didn't see anything by the water pump. I'll pressure test again and circle back.

 

^^^ This ^^^

When the seal wears out, coolant comes out of the weep hole(s), and drips onto the back side of the pulley, which then slings it in a fine mist EVERYWHERE, coating the inside faces of other accessories (alt, AIR pump, PS pump, etc.) and the front faces of all the components behind the front of the motor.

Also, an obvious shortcoming in all those pictures is, they're all taken looking down from the TOP. [insert obnoxious buzzer sound here] Coolant is heavier than air, therefore goes DOWN when it leaks in liquid form, not UP. Get up underneath the car and LOOK UP at it. In particular, look at the lower rad hose. Coolant will literally run down the BOTTOM side of it (toward the ground) when the seal leaks, and drip off at the radiator end of the hose. If you see coolant there, you need a WP. You might also want to check the bottle and make sure it's not cracked where the hose goes into it, at the BOTTOM. Doesn't look like that's your issue, since it doesn't fit the fact of coolant coating the inward-facing surface of the AIR pump and whatever all else, and therefore isn't likely to be "the right" explanation (see my signature), butt is a fairly common thing to happen anyway, and as such, deserves to be checked.

 

Thanks for the good comments. There's no bubbling in the tank but the engine was rebuilt about 6 months back and the water pump wasn't replaced at the time as it was working fine. This leak has been happening since, it has been more minimal it seems at some points since vs others and since I haven't seen any liquid really anywhere I've just continued to periodically refill the overflow reservoir. Not a good long term solution.

Tonight I got under the car. A tight squeeze as I don't have jacks or a lift yet, and tried to see what might be happening there and take some images which are included here. There is evidence of it all over the pully. I didn't see anything on the hose connection to the water pump. So, it seems like it likely is coming from there although it's slow and must be very fine.

I also did a pressure test. Started at 15 and after 10 minutes it was at about 14. No liquid was observed anywhere while the pressure was added. Leads me to believe that if it's only leaking slightly while the water pump pulley is moving this may well be the culprit, spraying it all over which I can see and as was mentioned by Sofa.

 

So...I'm following up with new info about this issue. Yes, it's been a couple of months. I did replace the water pump which did seem to help the issue. The level still was dropping in the reservoir tank but only slightly which I thought might be related to air pockets working themselves out after the new water pump installation. Turns out it has ended up being a much larger issue. Since I had the 305 rebuilt late last year I've had this issue, sometimes more coolant has disappeared than other times. I've also had smoke coming out of the exhaust which was whitish. I mentioned this to the shop a couple of times and wasn't able to get it scheduled back in until a couple of weeks ago as the shop was moving and they were inundated etc. They asked me to be patient which I have been. Anyway, I get the call after they get into figuring out what is going on and I learn that the block has a Crack in the lifter valley which has been allowing the coolant to mix with the oil. Of course I'm majorly upset about it. They tell me of course that the machine shop isn't responsible nor are they as it wasn't there when the engine was installed and they have no idea whst caused it. I say this has been going on for quite a long time and isn't it under warranty. They again say it wasn't like this and it's unfortunate, etc. So, I end up buying a 350 crate motor and they agree to major labor consideration. Thinking more about the history of the 305 and my trying to get it running as good as possible which it was thanks to Brian with Tuned Performance, this forum and tons of YouTube videos, I recalled that a couple of months after getting it back that I double checked the timing and discovered it was set to 0. The stock 305 should be ar 6 btdc. Mine with cam change, .030 bore was set to 12 btdc and once this was done, coupled with many tunes was finally good aside from the exhaust smoke which was largely evident at startup and idle. The engine seemed to have good compression and felt strong so it really is a shame. Of course I'm really ticked about the situation but realize I've got to focus on the solution. My question is that with the timing very retarded at 0 would this cause extra heat and stress due to the late combustion cycle? What do you all think? The shop said it wouldn't have caused it or added to the problem and that they set it at 12 which was incorrect as I did it myself. Attached are pictures of the Crack. Do you think their responses are reasonable? Thanks in advance for any insights.

 

That's the result of freezing. It's exactly where, and how, they most commonly crack from that. Very common in boats.

Bummer.

As far as "warranty", that would depend on who supplied the block. If it was your block, they don't really owe you anything. If it was theirs, they owe you a block.

No.

12 adv is a much better setting than the stock 6 adv. Especially with a stock tune.

This sort of thing is one of the unfortunate risks we all take when "rebuilding" an engine. (or anything else, really) The "core" - the wore-out thing you start out with and then spend all that money and effort on - is often the weakest link in the whole chain. There are tests that could have been done, butt they're labor-intensive and therefore cost significantly extra, and unless there was suspicion at the time or you specified you wanted it done, it usually isn't. Sometimes rebuilders offer that as part of their "standard package" or whatever, especially mass-producers, butt that automatically makes them less price-competitive, so it's by far not the norm.

If this was your own block, I'd say they're treating you reasonably well over it, by the standards common in that industry. At least they're working with you, and not just telling you to go pound sand, like often happens in such situations.

 

Thanks for the input. It is odd as all the engine work was done in south Florida so it was never close to freezing so who knows. Anyway, the car will have a 350 now which will be more fun to drive I'm sure paired with the 5 speed.

 

Doesn't matter where the engine work was done. What matters is the whole life history of the block since 1986/7. Which all it takes is for some jackbrain to leave it out overnight ONCE with no antifreeze over that period of almost 40 yrs now, which having lived south of the Mason-Dixon Line, I PERSONALLY KNOW happens ALOT around there, not least from having to replace customers' blocks they brought me with that crack in them.

At this point, It Is What It Is, and I'm glad there's at least some degree of happy resolution, although no doubt it still leaves some pain.

 

I'm really surprised that the machine shop didn't magnuflux the block and heads before machine work.

Decades ago, my father-in-law at the time (became ex-FiL and is now passed away) owned a machine shop and I worked in the shop for him right after graduating from college and before going into the USAF. I was a short block assembly guy so I didn't do any machine work. Anyway, once cleaned in the caustic, hot tank, every block and head was magnufluxed to check for cracks before any machine work was done. All of these decades later, I just assumed that this was still standard practice but what do I know?

 

Doesn't seem to be. Never has been in my experience, especially in "price sensitive" competition. Seems to me like something that only racing specialist shops do as a matter of routine; and other places, particularly the "mass" ones that compete on the basis of being $5 cheeeeeeper than the guy down the street, don't do it at all for their run-rate product, and charge extra to anybody that wants that level of assurance. Which the extra labor for pressure-testing or magging isn't really all that much. Butt I guess it's cheeeeeeeper to eat the warranty cost, which they minimize by other methods, than to verify the castings.

 

I'm having the same issue, and I had it pressure tested also, no findings at the time.