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Just a warning this is going to be cringeworthy for you professional mechanics and gearheads. This is my first purchase of an older vehicle and this is my attempt to teach myself how to work on/ diagnose problems on a car. Mistakes were made. I bought a 1989 Chevy Silverado c2500 off a guy on craigslist. I had never bought a car on craigslist so I googled what to look for. The engine looked great, it ran great. There was no heat or AC in the truck but it didn’t seem to affect anything and I didnt mind having the window open in April. I bought it in April and from April to about July/ August there were no problems. I noticed it had started overheating about that time. It would overheat by spiking to red all of a sudden then going back down to normal and staying there for like the next 10-15 mins then spiking again and going back down again. I also noticed it was idling rough around this time. I check the coolant and this stuff was gross. Muddy looking and apparently very low level. I figure I’ll do a super flush of the system and at the same time put in a new heater core because the old one was bypassed (cause of no heat) and fall and winter was coming up. I do the flush and put the heater core and add coolant and all i swell for about 3 days. Then it starts having the same problem. It would spike temp then cool back down, only this time it is happening more frequently. I looked at the coolant and i cleaned it out good but I noticed that the levels were low. I had just filled it up and theres no visible leaks. I kept on refilling and when the level was full there would be no problems but always after about 3 days of use it would start spiking again and I would notice the level is low. I would also notice that the heater would work when not spiking but when it would spike the heater would stop blowing hot air. This kept on for a while. I thought as long as I keep refilling I should be fine. I noticed that when I was on the freeway I would be fine, but when I was on the streets and stopped at lights, I would see more spikes. I noticed all within a day or so span, I had the spiking problem, a new whirring sound when accelerating, and loss of power. At that point, I decided to stop driving it and actually try to fix what is the root problem. Im thinking i was maybe too late.
I checked the oil and the coolant and there was no mayo looking substance. I did a chemical block test and I passed so I’m hoping theres no head gasket issue. Theres no white smoke other than in the morning when its cold. I thought maybe the water pump wasnt working correctly thus coolant not flowing properly and possibly evaporating due to not being pushed through the system properly. That might explain the whirring sound as well. So I changed the tstat, the water pump, and all the hoses at the same time. I drove it and the overheating went away, but I still had the whirring sound and decreased power. I just took it to get burgers one day and the next to the post office. It died at the post office. I tried starting it and it cranks but wont turn over.
Things I’m thinking it could be: head gasket or warped cylinder (although I'm hoping not) that is affecting the compression and explains where the coolant was going, whirring i read may be caused by a broken bearing in the alternator although there is no smell or electrical problems, i read maybe a timing belt issue, and an outside shot is maybe the fuel pump is faulty (there was also a decrease in mpg, theres the rough idle, and i read that faulty fuel pump may cause overheating spikes and loss of power as well as a whirring sound on acceleration).
Any ideas I can get would help. Am I on the right track?
 

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What size is the engine. 5.7 or 7.4 you have nit timing belt, its a timing chain, and thats not your issue, and nether is the fuel pump. You need to pull the spark plugs. Learn how to read them. They can tell you what is going on inside of your engine. Also once pulling the plugs, (1 at a time by the way) you need to do a compression check. Before all of this, spend some time doing some research. Start with you tube.
 

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If plugs check good, and compression test good, it could be a fan clutch issue, a radiator that needs to be roded out or replaced or both, but since your loosing coolant, you need to figure out where it is going. A radiator pressure test is the best way to do this. You can rent a tester from autozone, along with a compression tester. You buy the tool, but when you bring it back, they give you a full refund. Just tell them you want to rent the tool.
 

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If plugs check good, and compression test good, it could be a fan clutch issue, a radiator that needs to be roded out or replaced or both, but since your loosing coolant, you need to figure out where it is going. A radiator pressure test is the best way to do this. You can rent a tester from autozone, along with a compression tester. You buy the tool, but when you bring it back, they give you a full refund. Just tell them you want to rent the tool.
If you check the oil and it looks normal and at the proper level. then I would check the radiator and coolant. If you have a brown milk shake substance showing instead of antifreeze, then the oil cooler in the radiator failed and oil is leaking into the cooling system under hi pressure. oil pressure is normally between 15 and 50 psi with engine running. and the cooling system is running up to 15 to 18 psi under pressure. therefore oil will leak into the cooling system and not the other way around. If you have a strawberry milk shake look instead of antifreeze, then the transmission cooler in the radiator failed. If so, check the trans fluid level and condition. Either way the radiator and radiator cap must be replaced. the lack of power is from the engine getting HOT! New radiator and cap and a complete flush of the cooling system may save the motor. Just my thoughts.
 

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Thanks for the reply. When first overheating coolant was muddy. Did a super flush. Coolant looked good but still was evaporating/overheating plus this time loss of power and whining when accelerating. I changed Tstat and water pump and hoses. Coolant looked good after and no evaporating or overheating but now it will crank but not start.
Compression test came back good. Every cylinder over 155 psi and within 30% of that. Still no issues with substances in oil or coolant.
I’m starting to think maybe there were 2 separate issues, overheating plus maybe fuel pump?
 

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Thanks for the reply. When first overheating coolant was muddy. Did a super flush. Coolant looked good but still was evaporating/overheating plus this time loss of power and whining when accelerating. I changed Tstat and water pump and hoses. Coolant looked good after and no evaporating or overheating but now it will crank but not start.
Compression test came back good. Every cylinder over 155 psi and within 30% of that. Still no issues with substances in oil or coolant.
I’m starting to think maybe there were 2 separate issues, overheating plus maybe fuel pump?
on a no start situation where a vehicle ran before, it will be either a no fuel or a no spark issue. first, spray some carb spray cleaner or brake spray cleaner into the throttle body with the throttle held partially open. a three or four second spray should be enough. next button up the throttle body and then try to start the vehicle while holding the accelerator partially open. if you have spark and it starts for a few seconds it is a fuel issue. If it does not start, check for spark with an inline spark plug wire spark tester. if you don't have spark while cranking then that is the issue.
 

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You can shine a flashlight behind the injectors and see if they are spraying while cranking. If your TPS is bad and the ECM sees higher voltage from it than ~0.60VDC it will think it's in a flooded state and won't give it any gas. Same as if you were depressing the throttle while trying to start. I had an issue with my 350 overheating, had pretty good compression, 2 cylinders were 5PSI lower than the rest. No oil in the water and no water in the oil, no white smoke coming or sweet smell coming out of the exhaust. I was losing about 1/2 gallon a week. It turned out to be blown head gaskets between 2 cylinders on each side. These happen to be the ones next to the EGR ports, BTW. The ones that were 5PSI power than all the others were the culprits. You can see the white staining on the pistons.

IMG_0658.JPG
 

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If you check the oil and it looks normal and at the proper level. then I would check the radiator and coolant. If you have a brown milk shake substance showing instead of antifreeze, then the oil cooler in the radiator failed and oil is leaking into the cooling system under hi pressure. oil pressure is normally between 15 and 50 psi with engine running. and the cooling system is running up to 15 to 18 psi under pressure. therefore oil will leak into the cooling system and not the other way around. If you have a strawberry milk shake look instead of antifreeze, then the transmission cooler in the radiator failed. If so, check the trans fluid level and condition. Either way the radiator and radiator cap must be replaced. the lack of power is from the engine getting HOT! New radiator and cap and a complete flush of the cooling system may save the motor. Just my thoughts.
These trucks do not have an engine oil cooler in the radiator, only a transmission oil cooler.
 

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I think the OP had a leak which he has fixed, fixed it when he changed the pump and hoses.

The spike in the temp readings and the lose of heat at the same time, was due to the coolant being low. Both are very typical of a low coolant condition.

The noise under the hood, a noise that changes with the engine RPMs is likely the cooling fan clutch, a very common problem.

The no start is a new problem.
 
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