Automotive Engine repair Q

[JasonB]

The vehicle in question is a '92 Ford Ranger 3.0L v6, 160k miles.<br /><br />A couple monts ago, the seals in teh original water pump finally gave out so I installed one of the lifetime warranty AL ones from Autozone, installed new heater hoses, flushed the radiator, replaced the tstat. Since all this, the truck does something odd.<br /><br />About half the time, when it is up to operating temp, I can stop at a light and it sounds someone is rythymically tapping on something metal with a hammer and you can feel it when it does it. Doesn't always do it. It really sounds like something is loose and banging back/forth when you stop. It also does it some nights when I get home and continues up to a minute after I shut the engine off. <br /><br />I'm stumped....

 

[dolluper]

Re: Automotive Engine repair Q

Loose pulley on waterpump, running on after it's shut down usally caused by timing being offor too high of idle speed

 

[Bob_VT]

Re: Automotive Engine repair Q

Is the t-stat upside down in the housing? I have seen that happen before. There also may be a air lock in the system.<br /><br />You might want to call your local ford dealer and ask a tech if there is a sensor tied in with the water pump to the computer. I know it is tied in on 92 Taurus (differant engine).<br /><br />Bob

 

[JasonB]

Re: Automotive Engine repair Q

dolluper, I'll double check the pulley,a nd it's not run-on. The engine is off and it keeps doing it. <br /><br />Bob, I don't think it's a sensor and I'm certain the tstat is ok as it did this before I changed it, and I have suspected air-lock. Not sure how to check/cure that one though. The engine cools just as it should.

 

[Dunaruna]

Re: Automotive Engine repair Q

Its water hammer - air lock or stat problem (Pump blade clearance to block could also be an issue).<br /><br />Aldo

 

[JasonB]

Re: Automotive Engine repair Q

Since it happens for up to a minute after I shut the engine off,I'm hoping it isn't the pump and it has done it with two different tstats, the first had been in the truch for 30k trouble free miles.<br /><br />....I really hope the pump doesn't have to come back off, it's a pain in the posterior region.....<br /><br />What is the best way to eliminate water hammer? Drain, flush, and refill again? I should also mention that when it happens, you can lay your hand on the hose between the rad and the tstat and you can feel it pulsing with the noise. It doesn't just stop at once after shutting the engine off, it just starts fading slowly.

 

[Dunaruna]

Re: Automotive Engine repair Q

My next question was going to be "can you feel a pulse on the top hose", Seriously. First thing to do is bleed the system. Kits are available to do this or you can raise the level of the rad cap fitting using a funnel than seals inside the hole.<br /><br />Look at all the hoses (especially the heater hoses), are any connections above the level of the rad cap? If so, its a good point to bleed.<br /><br />If that doesn't fix it - pump is the next suspect.<br /><br />Does the stat have a jiggle pin? <br /><br />Aldo

 

[jimr]

Re: Automotive Engine repair Q

you can try using a floor jack under the front get it as high as you can get it and leave the cap off with it running.

 

[Xcusme]

Re: Automotive Engine repair Q

My bet is on an airlock. I found the absolute best way to purge the air from the cooling systems of late model cars/trucks is the use of one of these.<br /> Cooling System Air Purge <br /><br />Several companies make these. Find a repair shop that uses this method and you should be all set.

 

[JasonB]

Re: Automotive Engine repair Q

I finally got a good chance to get a better idea of what's going on. The popping is definetly teh thermostat opening/closing, very forcefully I might add. I can watch the upper hose expand/contract a bit with the snaps. I can also squish the hose rapidly and change the frequency of the snaps.

 

[Dunaruna]

Re: Automotive Engine repair Q

It doesn't nessesarily mean the stat is faulty, an airlock on the block side of the stat will cause what you are describing.

 

[Xcusme]

Re: Automotive Engine repair Q

Not trying to question your install of the thermostat, but, are you sure the spring coil of the thermostat is facing the engine and NOT the radiator?? I had a friend , many years ago, reverse install the thermostat, he torched a Buick engine when we went hunting, it was winter to boot.

 

[dolluper]

Re: Automotive Engine repair Q

Pop the cap off through heater control on defrost and run it,if pump is working it will through antifreeze out in a couple of minutes, you do have antifreeze in there?it should rise in the tank---50/50 mix if this works out it's either internal air lock or bad t-stat

 

[JasonB]

Re: Automotive Engine repair Q

Yup, the new stat went in exactly like the old one that had been in there for a couple years and the engine temp is pretty stable. The new one has been in there for probably a couple thousand miles so far.<br /><br />I just went out and played with the truck in teh driveway. It was still warm from my commute, so I let iyt idle and get back to operating temp and run for 10 minutes after that at various throttle levels and couldn't get it to replicate the problem. It only seems to happen after 30min or so of driving. As a side note, it seems to have plenty of coolant as there is quite a bit in the overflow/resevoir tank.<br /><br />xcuseme, Wish I had one of those airlift kits at this point and feel free to question anything.<br /><br />I think airlock is the culprit, but I'm seriously considering pulling the tstat this weekend just to be sure, I have an extra gasket left over that I bought in case I tore one when I put it in. I could then fill the block from the water neck on the top of the block. <br /><br />I'm just aggrevated since I have done a couple tstats and a half dozen flush/fills and never had this problem before.

 

[dolluper]

Re: Automotive Engine repair Q

IF your doing your t-stat put your old one back in it worked before I assume ,and fill through your re tank with defrost on high blower .pour it slowly

 

[ehenry]

Re: Automotive Engine repair Q

I'm leaning towards a bad t-stat. Dolluper is right on about making sure the heater level is all the way to hot so the heater core will fill up. I'd put the old t-stat back in and see if it still does it.

 

[Trent]

Re: Automotive Engine repair Q

The Ranger I had, had a placard to fill the block from the top radiator hose to prevent airlocks. Course it was a 2.8 and not the 3.0

 

[DJ]

Re: Automotive Engine repair Q

It's an airlock.<br /><br />Let it run with the radiator cap loosened to the first lock. Not off. It might get a little messy. As mentioned, have the heat on hot.<br /><br />If that does not do it. Remove the upper radiator hose, from the radiator, and fill through the hose.

 

[JasonB]

Re: Automotive Engine repair Q

May have this problem whilled. Went back out and ran it for a while with the cap off and spent some time squishing the upper radiaqtor hose forcing coolant back down. Drove it both ways to work today and if it "hammered", it wan't noticable. I'll keep an eye on it and hope that took care of it. Thanks for all teh advice.