[fnsteffen]

Hey everyone. I've been driving/rebuilding my '71 El Camino for several years now, but it's been my first vehicle to really work on and trouble shoot. For that reason, I find myself learning about things as they happen (or after they happen). That's been a good educational method for the most part, but now I'm hoping that it didn't cost me a bunch of money. Could y'all give me your advice?

I was driving on I-10 East to Houston yesterday evening and noticed that the engine started running warm. It wasn't shooting up to the top of the gauge, but it was hotter than normal. Suddenly, I started to get a fuel knock, so I pulled over immediately. The engine was hot, but the radiator was cool to the touch. Thinking it was a bad thermostat, I pulled the thermostat out, let the engine cool, topped off the water, and hit the road again. It ran a little cooler than normal, but everything else was normal for the next 30 miles.

Then it started to creep up again. It would get up to 200 and then drop down to 180. Then it got up to 210 and dropped again. Then it got up to 220, and I started looking for an exit (I was east of Luling, and there are only exits every 7 miles or so). When the engine started knocking again, I was freaking out, but I really wanted to get to the approaching rest stop as opposed to sitting on a narrow shoulder for an hour. I coasted into the rest stop (trying to avoid putting load on the engine), but by the time I got there, the gauge was damn near topped out at 250. Shut the engine off immediately, let my electric fans run, and opened the hood. Again, the radiator was cool to the touch, and the reservoir was full. Since it did this with the thermostat removed, I can only assume that the water pump is going out or I've got a clog in the system somewhere. Not wanting to push my luck, I called AAA and had it towed the rest of the way home. I'll hopefully get to work on it this evening if this rain stops.

What I'm worried about now is that I may have done major damage to my engine. It's a GM 350 Fast Burn motor with approximately 50K miles on it, and I haven't had any issues with it up to this point. As I mentioned earlier, all my knowledge up to now has been gained on a purely trial and error basis, so I'm kinda shooting in the dark.

The water pump looks easy enough to install, so I plan on replacing the pump and thermostat and flushing the system this week. While I'm doing that, what else should I look for to make sure I didn't do more damage?

I know I need to check my oil for water (currently running synthetic with 700 miles since the last change). But what other things would y'all recommend that I look at?

Many thanks for your help with this. I really appreciate you guys guiding a newbie along.


Much obliged,

-Steffen

EDIT: For clarity on the order of events.

[Robinls5]

I would try this. Remove the thermostat, Re install the goosneck-Fill with coolant and go for a ride. (close to home).
This is a guess, I sounds like your thermostat is sticking. Due to the fact the Rad. is NOT HOT and the temp gauge is going up and down.
Try it without a thermostat.......If the impeller came off the water pump, The gauge would bury itself and NOT come down.
Bob

[Tom Mobley]

>> "Thinking it was the thermostat, I pulled it out, let the engine cool, topped off the water, and hit the road. As expected, it ran a little cooler than normal, but I was running good for the next 30 miles."

Pretty hard to understand, it kept doing it after you pulled the stat? The same thing?

[fnsteffen]

Thanks for the reply, Bob. I actually tried that the first time it overheated yesterday. I pulled the stat, filled it back up, and started driving again. It was at that point that the temperature started fluctuating and ultimately overheated, which is what lead me to believe that the pump is going out.

Is there any reason the pump would run intermittently? Would the impeller be slipping part of the time?

I noticed a small water leak at one of the top bolt holes of the pump, so I think I'll just replace it anyway. Is there anything else with the engine that I should watch for to make sure I didn't screw something up? I'll be checking the oil to make sure I didn't blow a gasket, but I'm not sure what else could have messed up on account of getting too hot.


Thanks,

-Steffen

[Tom Mobley]

>>> "Is there any reason the pump would run intermittently? "

is it an electric pump?

[fnsteffen]

No, it is a belt driven pump.

Someone told me to check if the pump was going bad by trying to wiggle the sheave. When I did, it moved ever so slightly (enough to feel, but not enough to see). Also, there was a small amount of water leaking around the top right bolt hole.


-Steffen

[Brad Richardson]

Could be a partly clogged radiator. The water pump will leak out of the tattle tell opening in the bottom when seal and bearing failure is getting close. Have heard of the impeller washing out enough not to move enough coolant but IMO not the norm. Need a 50/50 mixture of water/antifreeze. Turn on the heater to circulate coolant thru the heater core when this happens to help get the temp down. DO NOT put coolant directly in a hot engine. Good luck and I feel the engine is probably ok at this point....Good luck..

[fnsteffen]

Thanks for the advice!

I'll most likely pull everything apart to inspect it as I don't want to leave any stone unturned. The blood pressure spike from yesterday still hasn't gone down, and I definitely don't want to risk having that again.

Is there a certain way to check if there's a clog in the radiator?


-Steffen

[forcd ind]

if you dont have a thermostat, you should be able to pull the cap, and with the engine running (do this cold) rev it up and you should see the water flow-prob not a bad idea to replace the pump, pull the back off the old one, ck the inpeller

[Brad Richardson]

I have seen stop leak type stuff clog radiators but if it has had none it is probably fine inside. Hard to say if it's up to snuff. The outer is easy enough to wash out and does help a lot. Can see major obstructions like leaves, bugs and such. Is it possible that the system has an air pocket? With a cool engine fire it up and watch the circulation with the cap off. FYI always give the upper rad hose a squeeze before taking off the cap. If limp your good but if you feel pressure let it cool a bit more.

[427L88]

The pump on our 427 went w/o warning. No noise, no leaks, and heck, I couldn't even tell it was broken UNTIL I pulled the back plate off and you could just hear the impeller hit the casting a touch. BUT the whole system got hot and under pressure.

Your engine is likely fine, but I pulled the oil filter ( and oil!) to examine it after our "event". I also did a compression test as the system pressure was pretty high.

Worst case is that the oil rings got too hot and lost their tension, which will show up as oil consumption.

[fnsteffen]

Just wanted to give you guys an update. After tinkering around with the cruck over the last few nights, I'm pretty sure I have a blown head gasket. In fact, I'm nearly positive that the faulty gasket is what was causing the overheating.

When I checked the oil the other night, it was still clean and normal. However, when I ran the engine with the radiator cap off, I noticed what I thought was steam coming out of the top. Since I've never run a vehicle without the radiator cap, it didn't seem all that odd that some steam would come out of it.

Anyway, I went ahead an put the cap back on and kept inspecting every nook & cranny of the engine. There's a small exhaust leak where the headers bolt to the block that I've known about but wasn't too worried about. When I looked at that, there was some liquid sputtering out of the leak. Hoping I was just running VERY rich, I released the pressure on the radiator cap, and the sputtering immediately stopped. It was then that I realized that the exhaust and cooling systems were being mixed.

My new hypothesis is that the faulty head gasket is letting exhaust into the coolant loop. The exhaust is then over-pressurizing the system and blowing all the coolant out of the cap (witnessed with the old and new radiator cap). The part that's still mysterious is that the radiator was cool both times it overheated on Sunday, but I guess if all the water was getting blown out of the cap, there wouldn't be anything to actually carry heat to the radiator and it would cool off due to the fans. At least, that's the only thing I can think of.

As much as I'd like to replace the gasket myself, I think I'm in over my head at this point, and I'm probably going to take it to a shop. What are yall's thoughts?

I apologize if all of this is obvious stuff, but as I mentioned before, I'm still pretty much a rookie. I appreciate you all looking at and pondering my situation, and I can't thank you enough for your advice.


Much obliged!

-Steffen

[fnsteffen]

So the first quote was $1,300 (minimum). That included 9 hours to pull the head, a machine shop testing and resurfacing it, the valve job, the new gasket, and flushing the coolant and oil systems.

Now that's just AWESOME.

9 hours to pull the head seemed excessive to me, but is that pretty normal?

Can anyone recommend another place in the Houston area I should talk to? I've never been one to make a decision based purely on price (since you usually get what you pay for), but I really can't afford a four-digit mechanic bill right now.


-Steffen

[pizzi-man]

You could do it your self and the cost would only be the cost of gaskets. It's not that hard of a job but is time consuming. by the time you get one head off it only takes 1/2 hr more to take the other one off. I did one head one time and a month latter the other gasket went out. Since then I always change both. You should not need a valve job with only 50,000 on the motor but you might take the head to a machine shop and have it checked for warpage and cracks.

[66 chevelle 496BBC]

this is easy to fix. take off you dist cap and move it out of the way crank engine untill rotor points forward and remove dist. remove battery lead and antifreeze. unbolt the accesories on the head in the way and remove intake with the carb still on it. unbolt exhaust manifold. unbolt head get checked. remove oil. clean block surface and put new fel pro gasket on.
put permatex pipe thread sealer on all bolts and torque properly. stick on the intake using the same sealer and torque properly. bolt on exhaust manifold and accesories. install dist with the rotor pointing forward as removed. put in oil and filter add antifreeze. put your pushrods inplace. you may count the threads showing on each rocker arm nut to get them near where they were and then adjust them with engine running or do it the other way. get the valve cover on. now clean up the messy engine oil if you did not put on the rocker arm clips designed to deflect the oil from go ing all over the place if you adjusted them while running. the only special tools are torque wrench and a distributor wrench.

jim