strange steaming radiator tale

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california3rdgen
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strange steaming radiator tale

Post by california3rdgen »

So I bought a broken down 89 Prelude, professionally rebuilt/resurfaced the head, put it all together, new timing belt, new water pump, new thermostat, new belts, etc... got it in fine working shape, fixed it all up. My son has driven it for 4 months, but he is pretty responsible. No real problems - just minor stuff that needs to be fixed on a 20+ year old car. But during Christmas shopping it starts to overheat on my son. He pulls over, calls me. I come up and drive it slowly home, watching the temp gauge go up and down, but never over 3/4 or so. In my garage I put in *lots* of water, but then I watch the radiator steam like someone is pouring water over hot coals - well, one or two hot coals. A steady, constant steam. I replace radiator cap. No change. I don't see any fluid dripping down on the floor. Strange. I check all connections and hoses - nothing unusual. This goes on for about 10 or 15 minutes minutes. Water temp gauge is fine the whole time, so it seems to have originally gone up because of low water. Finally I go out and buy a new radiator, thinking that it must have blown out and that is why the overheating, etc.. I install it, add fluid, bring up to temperature, and.... it continues to steam.... Very strange!

Then.... I notice that the exhaust is blowing out white smoke, with a funny sweet smell. And I see *the puddle* - looks like mayonaise on the ground. AGGHHH!! And the radiator water is gurgling away. Head gasket blown! Sooooo... after I recover from my agony, I tear the whole thing apart, take the head back to the shop where I had had it resurfaced 4 months ago, and ask them what happened. They checked it out and said it was fine, and did not think that the car had overheated to cause the head gasket to blow. They had installed a pressure valve that busts open at 240F, and it did not blow. The head was absolutely straight. Very strange!! They only surmise that one of the head bolts did not get tightened enough when I originally put it together. I'm sure I followed everything to spec - 22lbs, then 49 pounds, working from middle to outside. So I go and buy all new gaskets, put the whole thing together again. I did notice when I put it together that the middle two bolts, after tightening them to 49 and then tightening up others around it, were loose again, as tightening up the ones around the middle had relieved some of the pressure on the middle two - perhaps this was why the head gasket blew between cyl 2 and 3 in the first place???. Anyone had this happen?? Anyway, I fix up an oil leak along the way, got it all back together, and now.... the radiator still 'steams.' Enough so that when you stop at a stop sign you can see steam coming from under the hood...constantly. The engine is NOT overheating - temp gauge below 1/2 and fans rarely going on. So I am ready to go out and buy another radiator and try again, assuming that there are again some holes in the new radiator...??? . My basic question is what is going on with this new radiator - could a blown headgasket cause a huge amount of pressure in a radiator - enough to blow one out?? Seems strange. The radiator was one from Autozone, which could also explain things.... But it all is strange. Anyway, I will let you know if radiator #3 does the job, but if anyone has answers, I would love some.

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spiffyguido
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Re: strange steaming radiator tale

Post by spiffyguido »

Quite a story.

Can you see where the steam is originating on the radiator? It's entirely possible the new rad may have been a bad unit. The blown head gasket won't have caused any additional pressure in the system, so if the radiator was bad, it's been bad all along.

I have heard of people encountering what you described with the head bolts. Apparently the blocks will "walk" quite a bit when the head bolts are being tightened down. Thus, it becomes necessary to go over the bolts several times to make sure they are staying at the right torque. This also allows the head gasket to settle in and squish into place.

I also have a question about the original rebuild. After getting the head resurfaced, do you put on a new head gasket? If not, that's probably the reason for the break in the head gasket. Head gaskets are not reusable. You put them on, tighten them down. After that, if you have to take the head off down the road, it's generally a good idea to start with a new one.

california3rdgen
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Re: strange steaming radiator tale

Post by california3rdgen »

The original rebuild was done with all new parts - head gasket kit with all gaskets and seals around the head ($90) from the same professional shop that rebuilt the head - a very trustworthy place. Perhaps the 'head walk' took place as you say...

Back now to the radiator. Tthe latest... I exchanged the 2nd radiator (that was steaming) for a third one and put it in this evening. Warmed it up by driving around slowly until I could tell the thermostat opened up. Normal temp on gauge - a little below the 1/2 way mark. But again - more steam, from the area pretty much directly around and below the cap. Not too much, but I just shut it down and went inside. I remain confused. But one thot - the upper rad. hose is plenty hot, but the bottom one only warm. The cap is cool and the radiator itself not hot. But when I opened the cap it pretty much spurted out - as if the water had not really circulated at all and was clearly very hot. This is only after 10 minutes of driving slowly. I assume that after the thermostat opens the water should start circulating and both radiator hoses should be warm. So one guess is that the water may not be circulating correctly. However, I installed a new water pump when I originally redid the head/timing belt in summer. It seems a long shot that the water pump would go bad so quick. Thots? How does one check to see if the water pump is working? The thing is that the temp gauge doesn't go up past normal - albeit I am only driving it around the blocks at relatively low speeds.

california3rdgen
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Re: strange steaming radiator tale

Post by california3rdgen »

One more piece of the puzzle.... I went out and removed the thermostat, just to make sure that it was not in fact the problem (and hoping that somehow it was!). I also removed the fans, just to get a better view of the radiator and where exactly the steam was coming from. Drove it ten minutes, till the temp gauge was close to normal. Came in, felt the hoses. Top one quite warm, bottom one cold, radiator cold. Drove it another 5 minutes. Gauge started rising to about 2/3 (somewhat predictibly, with no fans to kick in, but it is only 48/9 degrees F/C outside. Came back in and shut it down. Top hose - very hot. Steam coming from top of radiator, *and from thermostat housing,* which I had tightened back on quite tight without the thermostat back in it. Must be a *lot* of pressure in that thing, and that would also make sense that the radiator steam is not from a direct leak but because of some very high pressure inside the system. I didn't bother opening the cap, but I am positive it would have blown a lot of fluid straight up. Meanwhile bottom hose is only slightly warm to the touch. Almost all the radiator is cold to the touch.

I let it cool down, then realized it might have a airlock, so I went back, put more water in (it was a bit low) and then left it running at idle with the bleeder valve open and the radiator cap off for a while. Lots more steam from the radiator this time - from all over the middle of it. And the fluid in the radiator is not that hot - I can put my finger in for a second or two. And now the lower radiator hose seems better - warm to the touch, so perhaps it is now circulating o.k. and it was an airlock. But still very strange - why the steam! I thought maybe something very simple, like fluid that spilled over that just needs to be burned off, but it just keeps steaming away...

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spiffyguido
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Re: strange steaming radiator tale

Post by spiffyguido »

Your water pump should be fine. A new one could be defective, but if you put a quality part it, that's unlikely. Airlock is more likely.

It's a common mistake to put the thermostat in backwards, so hopefully that isn't the problem. I assume you've got yours in the right way.

If there's no leak in the rad, I can't comprehend why it would be steaming. Are you absolutely positive that the 'steam' isn't coming from someplace else? Lower rad hose?

california3rdgen
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Re: strange steaming radiator tale

Post by california3rdgen »

Simple solution to what seemed to be a complicated problem. The steam was in fact coming from the radiator, but from the outside. I had collected all the radiator fluid in a bucket with a rather wide spout. When I tried to pour it back in the radiator quite a bit must have drained around the radiator spout and into the fins. I didn't notice this at all when I was pouring it on. The radiator fluid started steaming when the radiator became warm. I finally just kept driving it since there was no obvious leak and everything else looked good. The steam finally stopped after about an hour of driving (!). Mystery solved - rather stupid for me not to figure that out in the first place, but I guess I have always poured fluid in directly from the container, and it was not obvious at all that the bucket was leaking fluid around the cap. My son drove the car 200 miles yesterday to Sacramento and all is fine. It should be, with a new water pump, radiator, radiator cap, thermostat, and head gasket!



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