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| overheating blues https://slantsix.org/forum/viewtopic.php?t=14159 |
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| Author: | cshunley [ Thu Aug 25, 2005 9:45 am ] |
| Post subject: | overheating blues |
looking for some troubleshooting suggestions on an overheating issue on my 1962 225 signet. just got the radiator core rebuilt at the shop, and a new water pump that was leaking. when i dropped it off last week water was spitting out the top of the radiator. I just picked up the car from Clinton MD and ran it back to work. Temperature was medium between C and H the whole way, even during the stop and go. That was good. Temp even dropped a bit when I got up to speed. But as soon as I got off 395 tunnel 15 miles later and up here to union station, the needle pegged at H, just covering the left of H. I parked, let it sit for a few minutes idling and the gauge just sat there not moving. Did not boil over, but that indication right on top of H is not acceptable. I can't drive it like this. If I do, I will just toast the radiator and water pump all over again. i have a 1973 with electronic ignition that never overheats. That problem went away with the old water pump in that car. what are my next steps? this is the 225 with points and a single carter carb. there did not seem to be a head gasket leak. Learn how to enrich the mixture and see if I can set the timing, advance or retard? I would turn the distributor a few degrees in which ever direction is most likely to reduce overheating. Is that clockwise or counterclockwise? open the distributor and look at springs? get out my timing light and look for the timing mark? i just ordered an electronic distributor etc. it's a shame cause the car runs great, just is getting too durn hot. throwing money at mechanics who probably don't know themselves will bankrupt me. cshunley |
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| Author: | Slant6Ram [ Thu Aug 25, 2005 10:56 am ] |
| Post subject: | Next |
Your suggestions look reasonable. Another easy test is to pull some spark plugs to see if the mix is too lean. If they are bright white, then a vacuum leak or carb adjustment needs fixed. A timing light is a great tool to check your intial timing and check out if your advance curve is working. I've been told that redarded timing causes overheating. Counter clockwise will advance timing, but too far in either direction will cause problems. |
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| Author: | SlantSixDan [ Thu Aug 25, 2005 11:06 am ] |
| Post subject: | |
If you've got a new/recored radiator and a new water pump and the gauge is going "H!", then the first thing to do is check whether the gauge is telling lies. Run the engine with the radiator cap on the half-stop (cap is on, but not locked down) until the temperature gauge gives its too-high reading. Use a kitchen candy thermometer to check the top tank temperature with the engine idling. The result will tell you whether your engine is actually overheating, or if the gauge system simply needs attention—such as a new sender or a rubbed-off piece of sender wire insulation repaired. If you are actually experiencing overheating, we need to narrow it down to an airflow vs. water flow problem. Sounds like it runs cool at road speeds, but heats up when standing still or in very slow traffic. That's usually an airflow problem, either physical blockage of airflow through the radiator or improper installation of the radiator fan (...backwards...?). At higher road speeds, you usually have plenty of air going through the radiator from the car's forward motion, so overheating under those conditions is generally a water flow problem (clogged or gunked-up system, failure to include the coiled support spring in the lower hose, etc.) Should also ask what the status of your thermostat is. New? Old? Brand and type? Temperature rating? A lot of the catalogs incorrectly list a 195° thermostat as correct (it isn't) for your application. What kind of radiator work did you have done? New assembly of some kind? New core in your existing assembly? What kind of radiator cap (pressure rating, brand and type) is installed? New or old? Lean mixtures, vacuum leaks, retarded ignition timing and restricted exhaust system can also cause hot running, but let's make sure the cooling system is all the way debugged, first. Is this a 170, an iron 225 or an aluminum 225, BTW? |
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| Author: | Murch [ Thu Aug 25, 2005 11:08 am ] |
| Post subject: | |
Before you start replacing parts I would recommend starting with the basics. There was no mention of a thermostat replacement, I assume if a repair facility did the repairs, they replaced this (you might want to test it anyway-some cheapo parts can lead you chasing your tail). Does the system need bleeding? Try a pressure test on the cooling system-including the cap. What condition internally was the radiator? Perhaps the heater core could be the same way. You could by pass the the heater hoses to see. If everything in the cooling system checks out you may want to consider a leak down test (to eliminate a head gasket leak or worse). Should everything turn fine at this point, good. Then on to the next. Dale |
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| Author: | cshunley [ Thu Aug 25, 2005 12:46 pm ] |
| Post subject: | |
thanks gentlemen, i will continue to work the issue with your comments in mind and post the outcome. may be a few days. |
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| Author: | cshunley [ Fri Aug 26, 2005 6:19 am ] |
| Post subject: | |
interim report. i took notes from the postings down to the car. so far only deviation was that vacuum hose was loose and off from carburetor. would that affect temperature? how do you secure the metal piece at the end of the hose back into the carb? i just stuck it back in,but with engine wobble not sure it is secure. i guess maximum vacuum advance is at idle. wonder why though. bottom radiator hose was ok felt spring inside up until 4 inches from water pump. maybe that is collapsing but did not appear to be at idle. airflow was ok. 180 degrees is thermostat, they may have put a 195 in, i will check. and the cap is 16 psi not 14, which is the book. cshunley |
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| Author: | CStryker [ Fri Aug 26, 2005 8:24 am ] |
| Post subject: | |
Yes, a disconnected vacuum hose can cause an increase in temps, but it's usually not drastic for a small hose. As far as getting the barb back in the carb, I would remove it from the hose, mix up an epoxy of your choice, dab some on, and gently tap it back in w/ a hammer. If your max vacuum advance is at idle, that means you have it hooked up to manifold vacuum, as opposed to ported vacuum. Ported vacuum draws the signal from just above the venturi, where the vacuum behaves exactly opposite of in the manifold. (as RPM's rise, manifold vacuum drops, whereas ported vacuum rises) A little checking w/ a vacuum gauge should get that problem under control. |
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| Author: | SlantSixDan [ Fri Aug 26, 2005 10:47 am ] |
| Post subject: | |
Quote: interim report.
Gently tap it back in with a hammer until it stops. There is no need to goop it up with epoxy; it'll stay when tapped in.i took notes from the postings down to the car. so far only deviation was that vacuum hose was loose and off from carburetor. would that affect temperature? how do you secure the metal piece at the end of the hose back into the carb? Quote: i guess maximum vacuum advance is at idle. wonder why though.
Several possible reasons:-Because your carburetor is set up for ported vacuum spark advance, but the idle speed and mixture are set improperly and so the spark advance port is uncovered during engine idle operation, and/or the throttle shaft is loose and sloppy where it passes through both ends of the throttle body. Solution: Have throttle body rebushed if necessary, set engine idle speed and mixture correctly. -Because your carburetor is set up for manifold vacuum spark advance. Solution: Change nothing. It is not the case that all carburetors are set up for ported spark advance! Many of them are set up from the factory for manifold vacuum spark advance. Which type was installed from the factory generally depended on whether an automatic or manual transmission was specified. Take a look in any year's factory service manual. Note how there are two carbs specified for each engine/vehicle combo: one with manual trans, and the other with auto trans. The carb numbers are one digit apart from each other, and all published specs are the same in terms of venturi size, jet size, etc. THe difference (which they don't bother telling you about) is the location of the spark advance port within the throttle bore. Above the closed throttle plate for ported, below the closed throttle plate for manifold. Quote: 180 degrees is thermostat, they may have put a 195 in, i will check.
Definitely worth checking.Quote: and the cap is 16 psi not 14, which is the book.
16-lb caps were used with air conditioning. I was wondering if your shop had put on something incorrect like a 7-lb cap.How 'bout some ohmmeter readings off your temperature gauge sender? |
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