Okay everyone, here's my next issue. Just got done installing a Tom Langdon dual carb setup. The truck fired right up but gets to about 205 210 degrees while sitting idle after about 10 minutes. I pulled the thermostat and it is working correctly when I tested it. It is 180 degrees one. Even though it opened up correctly in boiling water I installed a new one and tested that one before I reinstalled. One thing I am noticing is it never seems though that the water pump starts pumping water. I keep the radiator cap open and watch the water inside of it while the engine is heating up and I never see any movement of any sort. Also, when the truck gets over 180 degrees I can easily squeeze the radiator tube on top and I'm not feeling any kind of water flow. When I turn on the heater in the truck it gets very nice and hot so that tells me that water must be circulating??? The temperature just keeps going up and up and never goes down while it is idling once it gets above 180 degrees. I drained the radiator and the coolent came out nice and clean, refilled and still having the same issue. Even jacked up the front of the truck and kept the radiator cap off to make sure I did not have any air blockage. Am I missing something simple?? Sent from my Pixel using The H.A.M.B. mobile app
To confirm the water is circulating, remove the thermostat and start again. This will force water to circulate since a closed or sticking thermostat is out of the equation. Remove doubt from your problem one at a time, then move on to other likely issues such as a vacuum leak as has been mentioned. Double check timing to ensure it is functioning, advancing and returning to normal at idle. Carb jetting could also need to be confirmed.
The port for the wiper vacuum is open to the atmosphere ... that isn't helping. You can't see the movement of anti-freeze because of a baffle in the top tank. Does your gauge return to zero when cold ? Maybe the needle has been bent. Stick a pocket thermometer in there to check actual temp once it's all back together. If it isn't boiling out coolant, it isn't boiling.
When I ran it for 15 minutes I used a thermometer inside the radiator cap and it was reading 203 degrees. It matched the inside Gage and also the inside Gage returns back to zero after it cools down. Sent from my Pixel using The H.A.M.B. mobile app
My inside gauge returns back to zero and when I let it run for 15 minutes and check with the thermometer the water at the cap is 203 degrees and pretty closely matches what it is saying inside. Should I not feel water running on the top radiator hose or at least feel really stiff?? Sent from my Pixel using The H.A.M.B. mobile app
No ... only 4 lb. system, & the volume isn't so great that you can feel it until high RPMs. You have to plug that intake manifold vacuum port ... I'm guessing it won't idle below 1000 RPM the way it is.
I love to solve overheating problems. Is this issue since the intake swap? If yes Someone already mentioned a vacuum leak and that is a possibility . The idle mixture screws may be closed to far in leaning the mixture . If you live in California or the freezing weather is over I would get rid of that antifreeze! It has nothing to do with cooling even though it's called coolant. For the summer just fun distilled water from the market and a bottle of Red Line Water wetter. That will end all overheating issues. That green crap is really only for freezing conditions and pure water dissipates heat way better. One more thing to check is your ignition timing. Too retarded will cause massive heat problems . Sent from my iPhone using The H.A.M.B. mobile app
First bs you so cal boys always thow out is the get rid of the antifreeze think but he lives in freeze your ass off and crack your block Iowa so that isn't a reasonable thing to do. Not what the problem is anyhow. A few things to look at Matt Vacuum leak causing the engine to run lean or idle mixture screws set too lean. Not enough coolant flow, Waterpump issue or restriction issue. Back when I towed a trailer a lot I would hull out a thermostat and just run the washer part. That gave enough restriction to get up to operating temp but didn't restrict it anymore than that. Ran my 48 that way every summer when I had the 350 in it. On restriction, is the radiator in good shape and does water run through it freely when you put a water hose in the inlet and watch how it comes out the outlet? On the air is the fan pulling enough air though the radiator at an Idle, I don't know how many if any you put on the truck before swapping intakes but these trucks are famous for getting warmer at an idle an then having the coolant temp drop to just above the thermostat rating when you ran down the road. My truck does that with a stone stock 250 in it. Runs 183 on a mechanical gauge over 40 mph and as soon as you hit a stop light the temp goes up an when you get back up about 35 it goes right back down. It may be that all you need is improving the air flow at low or no speed.
I will have to find a good article about this, I really don't understand how to best look for vacuum leaks and what it does when you have one. I am very new to working on trucks. Sent from my Pixel using The H.A.M.B. mobile app
I bought this about a month before I started working on it and I don't know if it was overheating to begin with or not to be honest with you. But funny you say that I can't get it to idle below 1000 rpms, I was thinking this was idling really fast and can't seem to get it lower. But then I really haven't investigated this much cuz I'm working working on the overheating issue. Sent from my Pixel using The H.A.M.B. mobile app
Everyone talks about vacuum leaks and that may be my issue, does anyone have a good article or link to a good article for a beginner on how to check for them on a stovebolt? Sent from my Pixel using The H.A.M.B. mobile app
Easy way to look is with a spray bottle of water. Start at the front of the engine and mist any area where air can enter the engine without going through the carburetor. If you have a leak the water will temporarily cause the engine rpm to change. Some use wd-40 or brake kleen or carb cleaner. I am not talking garden hose volume! Just kidding. Do not stop checking at the first leak. Check everything.
Matt, Look in the photo at 11 o'clock above the oil filter. See the open hole ? That's for the vacuum hose leading to the wipers. In the picture it appears to be open to the atmosphere.
Outside of hunting for vacuum leaks that may cause it to run lean an checking the timing to make sure it is right I'd suggest dragging a big fan or two fans out and setting them in front of it on full blast an run it and see what happens. That would become a yea or nea on the air flow through the radiator at low speeds and may also tell you that the cooling system it's self is good or bad.
One thing I am noticing is it never seems though that the water pump starts pumping water. I keep the radiator cap open and watch the water inside of it while the engine is heating up and I never see any movement of any sort. For the no circulation , did you check the waterpump , removing the thermostat as suggested would leave no reason for the waterpump to not circulate the water . Easy way to look is with a spray bottle of water. Start at the front of the engine and mist any area where air can enter the engine without going through the carburetor. If you have a leak the water will temporarily cause the engine rpm to change. Same idea but starterfluid , finding the leak it will raise the rpm:s , all thou normal idle is a must to get a smooth ride it shouldn't be the reason for uncontrollable watertemp at 1000rpm , did you drive it around , same problem with the temp raising ? Radiator is flushed and pass water ? Are you using straight water or mixed in antifreeze , 50-50 or 60antifreeze/40water will raise boiling temp . a link on the subject https://hellafunctional.com/?p=629 Wolf
Water exits the bottom of the radiator with now issues/blockage. Going to work on all the vacuum issues before going to any next steps...have a lot of suggestions here but that one seems pretty consistent.
My wipers work due to being a 12-volt system now??? I just know that they work....should I just plug that up?
Your the man!!! Why I love this site. Nite and day difference!!!! Everyone watch the video if you want to see what a vacuum leak will do. Now I will plug this up and let it run for 15 minutes and see what happens to the heating issue. Dang!! Site won't let me upload video. Sent from my Pixel using The H.A.M.B. mobile app
Okay everyone, thanks to all of you and especially 302GMC the overheating issue is now a non-issue. Thanks for the support everyone and will consider this thread officially closed. Thanks!
But you must remember this is the first vehicle I have ever worked on. Sent from my Pixel using The H.A.M.B. mobile app
One last question though. I did plug up that hole but people said that was the vacuum for the windshield wipers. If I have Electric windshield wipers do I still need to use this? Sent from my Pixel using The H.A.M.B. mobile app
Well no. Old trucks, (as well as early Chevy's and others), used wiper motors that ran off of engine vacuum. That's what those engineers in Detroit provided before electric wiper motors were factory equipment. You've got electric, (perhaps an aftermarket), which is a better solution so you have no use for a vacuum source for the wiper system. It's blocked off, you're good to go!!!
The Jalopy Journal
