Sorry for a long post but need to vent. OK I hang out in the first gen site. Issue: 305 TPI probably blown head gasket. Per shop. Back story: after hospital stay drove car and brakes failed completely. Nursed back home and because of brain boiling heat and no available garage space took it to a Nationwide chain. Fix my brakes. OK, well we have to replace rotors. " are the blue" We don't know, but warranty requires it. they were not bad, Oh front calipers bad. Warranty requires it. OK. OH there is water coming out of the water pump weep hole you need a new water pump. NO, I'll do that myself. OH the radiator is busted and leaking, Provided videos of coolant coming from the stupid plastic tank and the radiator. I'll get you a radiator. No that will void warranty., the one i found was $200 cheaper than I ended up with. Oh you have a blown Head gasket, there was no water in the block. HMM, where did the water from the water pump bleed hole come from? SILENCE. Pack it up Ill pay for the brakes and a tow truck will pick it up! A$$holes. Now bottom line we ar over a year down the line and and want to get it fixed. 85 IROC Z 305 TPI sitting with water in the crankcase for that long, But not run except what the shop did.? Questioning whether to replace the whole motor or just head gaskets, or rebuilt heads. Always heard bad thing about 305 heads. Code F Motor, any different from any other 305 except the TPI? ONLY +/- 46K miles. Thoughts?

 

Ignore all the shop's diagnosis. Change the oil, fill it up with water, and see for yourself exactly what it's doing.

 

That was my initial thought. Life gets in the way. When I retrieved it I got a new battery and then checked the oil and the level was about three inches high no milky but not really good for synthetic. Just dont want to ruin the shot block if not needed but also dont want to lose any compression going to a permatorque gasket or something like that hat is thicker to seal a warped head. Rebuilt heads are pretty cheap but not original like it is now.

 

I agree with Komet, do your own diagnostics. No water in oil is a good sign. I wouldn't be surprised if the head gasket is good.

 

Don't start it. Drain the oil and see what comes out. If it's oil and coolant, you'll see it. Coolant will come out first, then oil.

 

The TBI 305 heads were pretty lame. TPI typically got the better stuff. Assuming nothing was changed out by a previous owner, you should be okay. You can verify the casting numbers if/when you pull the valve covers.

 

The TPI heads (416 most usually 86-back, 081 87-up) were VASTLY superior to the TBI ones (191). Since yours is 85, it has the earlier style heads, 416, which is VERY common. MUCH more common than 081, fortunately for you. Keep in mind also, your intake won't bolt up to 87-up heads such as 081 or 191, without some extra work, so that's best avoided without even making a stink about "TBI" as such. IFF you even get to the point of needing them. And if you do, accept no castings other than 416 or possibly 601 which are a good casting also and were used on a few TPI motors as well as in a fair number of truck applications. If they hand you ANY other heads and give you the mealy-mouth about "just as good" or "makes no difference" or "all the same", nod your head politely, get the #s they want to give you, come on here, and we'll tell you whether they've got their sunshine hose stuck up your ... where the sun don't shine ... and ready to pump.

The difference in compression you'll get from the different head gaskets is TRIVIAL. Among all the issues facing you, it's down near the VERY BOTTOM of the list. If it comes to that, FelPro is as good as any and better than most. Don't worry about it.

As said though, you're working on an ANTIQUE car; 41 years old next month (85s came out in late Aug 1984). It's beyond foolish to pay "shop" (not really even sure what that is, I always thought that's what women did when they wanted more pairs of shoes or something) to indulge in your antique car hobby FOR YOU. No sense paying to put somebody else's kids through braces and college when you could be keeping that money for yourself, or your own kids if you have any. Then, you could handle it wisely: you could spend 90% of it on whiskey, women, and good times, and the other 10%, you could just WASTE.

Tackle it YOURSELF. Quit effffing around with people trying to pry their way into your wallet. Drain the oil and change it, see what comes out, and how much of each.

If there's coolant in it, as opposed to water (which could be rainwater for all we know, you didn't really address that possibility), then there's acoupla sources for it. Can't be the water pump; that can leeeeeeek, as you've found out, butt not into the crankcase. Besides head gaskets, intake gaskets can do that though; the section of their gasket across the bottom of their 4 water ports, connects directly to the crankcase. If you see or smell coolant on the intake ANYWHERE, then those are immediately suspect.

I'd suggest, if in fact the substance in your oil pan is indeed coolant, that you take off the intake CAREFULLY (you'd have to do that to get to head gaskets ANYWAY) and look closely at the water port parts of their gaskets. If those look compromised, which the way factory gaskets fail, will be pretty damn obvious, you've most likely found your problem. If they look PERFECT - and I don't mean just "good" or "OK", I mean PERFECT - take some good photos and post them on here, and we'll render our judgment on them. You may not have to tear into it any further than that.

And of course, replace the WP, rad, coolant bottle, hoses, and/or whatever other external items are leeeeeeeking. YOURSELF. Which of course, you'd have to do ANYWAY, head gaskets or no.

 

I wouldn't say no water in the oil. The level is very high. Not milky but has been sitting for quite a while so surely separated. Level is high enough that my drain pan will likely not hold it. Main issues are 1. Been sitting with probable water/coolant for a long time. 2. As per my last sentence in the original post, it is a code "F" TPI motor. What is the difference between that and any other coded pre-roller 305? Compression? Cam?, or are all of the 305 short blocks the same build?
Had a line on a TPI 350 from a totaled Vette, but Wifemaster blocked that. It would have been a steal.

 

Yeah, that is why I didn't start it. I don't know how much the shop ran it. It ran fine before they got it for the brake job. I should have been patient until I was able to do the brakes. Now I don't really want to talckle pulling the motor in the driveway, but I can re-built it if I need to. Never done a 305, seems a little futile. Mental thing. But the car was born with it.

 

I am the only owner, bought it new April 14 1985. I thought all the 305 heads were the same? It is TPI and ran very well for what I need it for, which drive when I neeed to go a long way cooley.. Daily is a Silverado, and other toy is first Gen 68.

 

Sofaking., thanks for your comments, but the only reason I took it to the shop for brakes is because I had been in the hospital for 10 days and was weak as hell and the weather was brain boiling hot and car was stuck in the driveway due to house issues. Rad was replaced as the plastic tank was separated from the core. They said it froze, but I had checked the coolant level because I was going to change the upper hose for a minor leak at the Rad. I think the overheated it and blew the Rad and maybe head gasket. I think I got screwed but didn't want to spend the legal $$ to maybe get screwed again. Hindsight is a beyotch. The info on the heads is much of what I was looking for. Didn't know if cam was different for the TPI? starting a new job Monday after being retired so time to get the toys up to speed.
Thanks

 

It could have frozen, butt since the tank in that construction is aluminum, and aluminum fatigues from repeated application and release of stress, that's kinda just one of the 2 normal failure modes for that type of rad. The end plate of the tank, that the tubing is welded to, has sort of "fingers" that wrap around the edge of the tank and crimp in place around it, and those can eventually give out. The other failure modes being of course, the plastic cracking, and the rubber seal between the tank and the core giving out. Any of these things can occur naturally just from age and use, or by freezing.

Head gaskets don't often "blow" in engines as young as ours. Much less common than 60s and earlier vehicles; the materials they're made of are just ... better. As said though, stock intake gaskets VERY OFTEN fail, in a way that can allow coolant into the oil; they just more or less turn into mush and dissolve. A more common failure than head gaskets. Generally you have to REALLY REALLY REALLY REALLY overheat a motor to wipe out HGs; like, to the point that you can see other damage from the outside. It's hard to believe that any professional "mechanic" (yeah I know) would let a car they were working on overheat THAT BAD while working on it; they'd have to, like, start it up out in the parking lot, everybody go to lunch while it's running, and come back an hour later. It would make SO MUCH steam, smoke, noise, smells, etc. in the meantime, that it would have been noticed; and other vulnerable parts, particularly hoses, would fail during the process as well. I'm just not seeing a bad HG as all that likely, and certainly not inevitable to the point that I'd just plow into it and tear it down that far.

If in fact a HG is bad, you can test the coolant for exhaust. No other failure, besides cracked castings, will produce that. Heads usually crack between the valves, butt that usually lets coolant and combustion exchange, not coolant and oil. Cracks are by no means rare either, so they can't be ruled out. If it turns out that you DO have exhaust in the coolant, and you tear it down and find no HG issues, then it's time to get the heads pressure tested; and if they're good, then the block. Which incidentally, if freezing IS involved, blocks usually crack first (before heads), and they do so along the surface just above the lifter bores, under the intake manifold; that lets coolant into the crankcase, butt of course not exhaust into the coolant.

So: the logical chain of troubleshooting looks like this:

Drain the oil. Determine what the extraneous fluid in it is.

Coolant: pop the intake manifold off first, check its gaskets around the water ports, if they're bad, replace them, start the troubleshooting process over.
Not coolant: change the oil, drive the car.

If the manifold gaskets aren't bad, collect a sample of coolant and test it for exhaust, and pop the heads. HGs almost always blow between the center 2 cylinders first: that's where the stresses on them are highest even in a normal situation, and where overheating causes the most further stress. Almost always that's where they'll fail for any reason. If they fail between a cyl and a water jacket they'll almost always have failed already also in that spot, which is VERY EASY to spot. Yerbasic brown stain across the narrow place in the exact center of the HG. If they're OK there, then they most likely didn't fail between coolant and crankcase, either. Odds are about 90% that if they've failed at all it'll be between the 2 center cyls; if they've additionally failed anywhere else, about 90% odds it'll be between coolant and a chamber; leaving VERY LITTLE probability that they could possibly have failed between coolant and crankcase and not failed elsewhere. If they're good then you have cracks. Inspect the block closely right above the lifter bores. If that's OK then have the heads pressure tested.

You didn't say where you are, or whether it had antifreeze in it before all this drama started, so it's hard for me to guess how likely freezing might have been. Even if you're in a place that doesn't freeze though, it should ALWAYS have antifreeze in the coolant, because that NOT ONLY lowers the freezing point (hence the name anti-freeze), BUTT ALSO raises the boiling point, which of course prevent the spewing and whatnot; and if you're in a place that doesn't freeze, then odds are, you NEED the anti-boil benefit JUST AS BAD as a car in a cold place needs the anti-freeze property. ALWAYS ALWAYS ALWAYS ALWAYS keep your coolant between about 30 and 50% anti-freeze even if your place never freezes.

 

There has been lots of good, practical advice given here, but not really sure what it is you are looking for based on your follow up questions/statements.

Regarding the '85 305TPI "F" code motor, it also shares the same block/heads/internals with the 305HO "G" code motor. It also shares the block/heads/internals except for the camshaft with the LG4 "H" code motor. This is all for '85. Other years have some other differences, but generally anything '85 or earlier will bolt right in. '86 changed to one piece rear main seal and '87 changed heads with a different intake manifold bolt angle. Neither of those things are dealbreakers, there are ways to accommodate. There are also 305 motors in other GM vehicles. Other than the 305HO in the Monte Carlo SS, all of the others will be some variant of the low output LG4 305. Even with all of this info, I would not be considering replacing the 305 you have with another 305. If you're at the point of needing a new motor, a 350 isn't really any more expensive and it's the same amount of work.

As far as rebuilding the motor you have, I would not do that either. Back to the point above. The cost to rebuild a 305 is the same as a 350, so it makes no sense. There is no increased market value in keeping it a 305 over a 350, unless it is a super low mileage, all original collector car.

I would see what you are dealing with as far as the motor you have. Drain the oil, see what comes out. Put new oil in it, fire it up and see what happens. If the bearings are damaged from sitting with water in the crankcase, then the motor is trashed anyway. Really nothing to lose. Maybe it's fine and just needs head gaskets or maybe its a goner. Once you know that, then you'll know if you're into a motor swap.

 

Just a thought. When checking the oil do you pull the dipstick, wipe it off, reinsert and pull it out again to read the oil level? I have experienced on engines that have not been run for a period of time if you pull the dipstick and read directly they can show high due to wicking up the dipstick from temperature differences.

 

I do both, but I can’t say that I have seen a difference on a motor that has been sitting for at least a day.

In this case, I would be checking the dipstick first and then draining while watching what comes out.