OK...I've got a rebuilt 263 (straight 8) that was redone 5 years ago, and has 6,000 miles since. I checked the antifreeze yesterday for the first time in awhile, and noticed it was low...I had to add a couple of quarts. Just for the heck of it, I rented a cooling system pressure tester from AutoZone, pumped it up to 7 pounds, and it held pressure fine. I took it for a ride and got it nice and warm, waited 15 minutes, took off the pressure cap, and tried again. This time, it lost maybe a half pound of pressure in 2-3 minutes. It runs great, no smoke from the pipe, no missing. It runs cool, never comes close to overheating. The only clue that something may be wrong is that it leaves a little drop of water from the road draft tube and snots up the oil filler with condensation. Neither smells like antifreeze. I've got bad vibes of cracked heads/blocks, etc. Any ideas? I'm not feeling good about this...
I'm going on memory here. But, Unless you have modified it from original that pressure after loss is still high. I believe; Originally your car had a 5 lb pressure cap. ---------- Post added at 05:48 AM ---------- Previous post was at 05:34 AM ---------- From AACA Buick forum; __________________
Have you owned this engine since it was rebuilt? A crack would be very unusual unless the engine has been severely overheated. One thing you can do is find a garage with a test kit that will detect exhaust gasses in the cooling system. The test equipment is not expensive (it looks like a glorified turkey baster), I would think that you should not have too much trouble finding a repair facility with this equipment. If there is exhaust gas present in the coolant, obviously there is a path from the combustion chamber into the cooling system. Think weeping headgasket. Yup, it could be a crack, but when I have a runny nose, I think about a cold, not the Ebola virus.
I've had the car the whole time...my local machine shop rebuilt the engine and there were no cracks then. It's always had good antifreeze in it and has not been overheated. I'm taking the car over to the local radiator shop after work to see what he has to say...he's been in business a long time. John (first of all, I appreciate the "Don't Jump" attitude--I always think the worst!), I actually wondered about the head gasket. I never retorqued it after it ran, and it's a lacquered metal gasket. Might be worth seeing if all bolts are up to torque (in order, of course). Thanks...
Yup;- I'd definitely re-torque it...The manuals say one should be checking the torque every 10,000 miles or so, but I've never seen anyone do it. But after a rebuild it is advisable, especially if you used the original headbolts.
I'll be doing that over the weekend...along with checking the trans. cooler and clamps, just in case, because it used a decent amount of antifreeze yesterday over the course of 60 miles or so, probably a quarter to a half quart. The oil level's not up, and there's no smoke, and it's still running fine...we'll see what turns up.
Well, not much turned up. The head's torqued, all fittings are tight. The inside of the valve cover was filled with snot, and it never has been before. I'm pretty convinced I have a head gasket issue (hopefully not worse). I don't believe it's into any cylinders, however, because none of the plugs looks washed out. Sigh. I think I'll be taking the head off to check things out, especially since the coolant level is going down on a daily basis now.
Sorry to hear that; - You didn't have the seats reground did you? Hopefully it's just a bad gasket...
It has hardened seats and new valves (7 years ago). I'll update when I get it apart, but it might not be for a couple of weeks...
Pressure test the cooling system with the spark plugs out. Leave the pressure tester on for quite a while. Turn the engine over with the starter. If one cylinder sprays water, that's where the problem is. If it doesn't, it's probably something that is opening up as the engine heats up. Still could be a headgasket.
I had a similar problem with a mini van - it was sucking coolant into one of the cylinders. It ran great and never overheated but the coolant level would frequently be low. There was always a little steam coming out of the tail pipe.... Eventually I sold it just the way it was.
When I was a kid, I remember travelling across Death Valley and noticing the stops that said "water." I asked my dad - why? (in full disclosure, I asked why people died of thirst if there were faucets every 100 or so miles) - he said it was because cars used to lose water when they got hot - no coolant tank/recovery tank - thus they'd lose too much water and without those stations would overheat and die.... still think they're on the hills around DV... Are you sure it's not just water that vented out the overflow tube? 5-7 lb cap will occasionally burp water, thus a quart or two loss every 5k miles isn't something to be concerned about (especially since you've done the due diligence and checked for torque settings and leaks). Yes, losing a couple pounds when hot seems like a problem, unless, of course, the motor was off and cooling - then it would naturally start to lose pressure as the motor cooled.
I rented a combustion tester (the first one yesterday was faulty)...tomorrow after work I'm going to take it for a spin and test the cooling system for gases. I'm not sure if I want there to be some to make this an easier process or not! I'll keep everyone updated.
I would say check your heater core she may be ready to blow... and next put a overflow bottle and see if you are losing anything out the top of the radiator cap
Well, I ran the combustion tester over the radiator and it showed no signs of leakage. I reran the pressure test and it dropped a half pound quickly and stayed there for at least 5 minutes. I think the half pound was in the instrument itself. I don't know what happened, but at this point I'm just going to keep an eye on it. Maybe the GM sealing tablets sealed the leak. I am going to switch back to a 180 thermostat (it's at 160 now) and put a new radiator cap on it. I'll keep everyone updated should things change.
