Gmc motorhome valve covers and overcooling?
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- เผยแพร่เมื่อ 8 ก.พ. 2020
- My 76 GMC motorhome renovation and customization, fixing leaky valve covers, and trying to figure out an overcooling mystery. please any thoughts are appreciated. the thermostat is a new 190 degree and the 160 degree it replaced did the same thing. getting idol temps over 150 without blocking the radiator are impossible.
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Somehow that strange music just permeates the work and matches the "wrenching"!
The thermostat is probably stuck open. The engine won’t run properly until it reaches normal operating temp. It’s not great to run it cool for a number of reasons.
It looks fantastic, great work!
You never dropped a stud or anything onto the ground! Gold star!
I'm a bit late to the party here... but it's been noted that the valve cover baffle over the PCV valve is quite a bit longer on the motorhome OEM valve cover. Using regular car version valve covers will allow the PCV valve to pull more oil into the intake. Likely due to the increased blow-by in the motorhome application.
Let us know if you notice increased oil consumption.
The reason Oldsmobile used a thermostat bypass was for a few reasons. The first being it allowed the entire cooling system to warm up gradually together. The radiator, engine block, heads & intake manifold. The second reason was it helped limit water pump cavitation.
How did you make or where did you get the magnetic wire looms?
GM used intake gaskets that had baffles to increase water temperature by increasing water pressure at the water passages. In some applications these baffles are missing to increase water flow and promote cooling. You may have the wrong intake gasket installed. These olds engines had many different applications to include dump trucks and formula firebirds..
Good info to know. Thanks.
@@getoutgadabout3423 high pressure gives off heat while low pressure picks up heat. Although the rad cap has a pop off pressure release, the thermostat does not. Running a bit cooler may have to do with the heat range of the spark plugs. Spark timing may contribute to engine temp also.
Temps are good now. Runs a consistent 178 in 95 degree weather at idol. I need to test it under load soon.
Maybe the loop to the domestic water heater ?
Yea that would be something to look at , but........ I removed all that. Only the heater core Is hooked to the engine. And I made sure the heat was turned off while testing lol.
I'm pretty curious about your headlights and the signals.. I want to do the same.. what did you buy there?
I made the back plates out of a sheet of 1/16” diamond plate and painted it black. The signal lights are flush mount truck lights. The trick was getting the shape of the diamond plate inserts just right to fit nice and tight.
The headights are just led headlights. I did have to clearance the headlight buckets to fit the heat sinks for the bulbs. I’ll try to show them in the next video if your curious.
Trent Gustus
These are the signal lights I used
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has some 1 taken in the thermostat out
I see that you are in New Jersey. So am I. Can I come over to see your GMCMH? I can use some idea of what it looks like stripped. Mine isn't there yet.
I’ll tell you what. Tubby should be to the point of getting some test drives in the spring so maybe we can meet up and you can take a look.
@@getoutgadabout3423 Sounds like a plan.
how come you not clean the air filter cover look bad
I've never trusted E-Bay, too many horror stories. ;-)
Ok video....
BAD choice of music...xxx noise... noise...noise... XXX
If you are over cooling, there are only two ways that can happen 1. The thermostat spring is too weak and coolant is forcing the poppet open. Never use standard duty thermostat, use a Robert Shaw / Mr Gasket high performance type. The are more accurate. If you have one of these, test it in hot water and see when it starts opening. 2. Too much coolant is bypassing the thermostat. GMC had a special water outlet fitting for the heater/Water heater hose. It was a full 5/8 fitting, but the hole inside that the coolant passes through was only 5/16"! If you replaced this with a standard fitting, the engine will over cool at low speed.
Thanks for the thoughts. I will be doing the hot water test. All the fittings are as was came with the coach. Haven’t replaced the water neck or the fitting in the head. I have a suspicion as to where the problem is and if i can get home at a decent hour I hope to start examining it tonight.
@@getoutgadabout3423 Thought I would keep this thread going. I have a Toyota Matrix does the same thing, but, it is an aluminum block. Too much
retained heat is catastrophic. I would agree with most of what you say, rad crossflow, coolant bypass, heater restriction etc. GM likely designed sizing for " under load " conditions in arid areas. Also the Turbohydramatic torque converter churns the fluid a LOT less at idle than under load. Make sure the clutch fan free wheels and consider an electric cooling fan. My remedy was to block off most of the rad surface save for 2 12" dia. & diagonal cut outs. Even with this the Matrix drops temp at idle. Just some thoughts. K.Of course this is ONLY for winter driving. In summer the heat builds up.
Are you using a RobertShaw high flow? It's the only one that'll work right: www.gmcrvparts.com/ProductDetails.asp?ProductCode=G330-195. You don't want the ones that have bypass holes in them.
yea its a robertshaw without a bypass hole. going to remove it again and see if it stuck
@@getoutgadabout3423 Somebody cross-posted this vid to Facebook and mentioned that you seem to have a lot of airflow at idle. Is the thermostatic clutch on your fan locked up?
@@christodarsch9544 not locked up but I ordered a clutch yesterday thinking it might be running at to high of an rpm. we shall see. thanks for the thoughts.