1979 Olds 98 LS: cooling issue
March 20th, 2019, 09:18 PM
#1
Registered User
Thread Starter
Join Date: Mar 2019
Posts: 2
1979 Olds 98 LS: cooling issue
I got some problems with the coolant system of the 350 engine. When driving the car, the level in coolant reservoir will go up over the "hot" mark. When parking the car, you can watch the level go down until the reservoir is nearly empty.
An idling engine will cause bubbles in the reservoir. When I open the radiator cap while the engine is running, every 30 sec there will swash out coolant.
What I also noticed, is that the upper cooling hose will contract when 1) engine cools down 2) when I rev up. Acc. to the seller, water pump has been changed recently.
Looks all this to you guys like a poorly vented cooling system or more like a blown head gasket?
BR Ronny
An idling engine will cause bubbles in the reservoir. When I open the radiator cap while the engine is running, every 30 sec there will swash out coolant.
What I also noticed, is that the upper cooling hose will contract when 1) engine cools down 2) when I rev up. Acc. to the seller, water pump has been changed recently.
Looks all this to you guys like a poorly vented cooling system or more like a blown head gasket?
BR Ronny
March 21st, 2019, 04:42 AM
#2
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 48,269
I got some problems with the coolant system of the 350 engine. When driving the car, the level in coolant reservoir will go up over the "hot" mark. When parking the car, you can watch the level go down until the reservoir is nearly empty.
An idling engine will cause bubbles in the reservoir. When I open the radiator cap while the engine is running, every 30 sec there will swash out coolant.
What I also noticed, is that the upper cooling hose will contract when 1) engine cools down 2) when I rev up. Acc. to the seller, water pump has been changed recently.
Looks all this to you guys like a poorly vented cooling system or more like a blown head gasket?
BR Ronny
An idling engine will cause bubbles in the reservoir. When I open the radiator cap while the engine is running, every 30 sec there will swash out coolant.
What I also noticed, is that the upper cooling hose will contract when 1) engine cools down 2) when I rev up. Acc. to the seller, water pump has been changed recently.
Looks all this to you guys like a poorly vented cooling system or more like a blown head gasket?
BR Ronny
March 21st, 2019, 06:19 AM
#3
Administrator
Join Date: Oct 2009
Location: Poteau, Ok
Posts: 41,064
While bubbles may be a sign of a blown head gasket, it could also be a sign of air evacuating a freshly filled cooling system. Water expands and contracts with temperature, so your reservoir level will be higher at temp and lower when cooled as the coolant leaves the radiator and returns. Two questions, what is the operating temperature of the engine at speed and at idle? If you fill the reservoir, will it maintain that level or does it drop? Water dumping out of an open radiator could happen normally depending on your idle speed and the cycling of the thermostat with water temp. Radiator hoses can collapse as the cooling system temp drops because it creates a vacuum.
Bottom line, you can borrow a cooling system pressure tester at some auto parts stores either free or a small fee. Follow the directions and trouble shoot prior to throwing parts at it.
Bottom line, you can borrow a cooling system pressure tester at some auto parts stores either free or a small fee. Follow the directions and trouble shoot prior to throwing parts at it.
March 21st, 2019, 12:15 PM
#4
Registered User
Thread Starter
Join Date: Mar 2019
Posts: 2
The cooling system is not supposed to be vented. It's sealed with a 16 PSI pressure cap. It sounds like a head gasket issue or other problem. I would start with a cooling system test to figure out if there is a leak. Follow this with a leakdown test to determine where that leak is.
While bubbles may be a sign of a blown head gasket, it could also be a sign of air evacuating a freshly filled cooling system. Water expands and contracts with temperature, so your reservoir level will be higher at temp and lower when cooled as the coolant leaves the radiator and returns. Two questions, what is the operating temperature of the engine at speed and at idle? If you fill the reservoir, will it maintain that level or does it drop? Water dumping out of an open radiator could happen normally depending on your idle speed and the cycling of the thermostat with water temp. Radiator hoses can collapse as the cooling system temp drops because it creates a vacuum.
Bottom line, you can borrow a cooling system pressure tester at some auto parts stores either free or a small fee. Follow the directions and trouble shoot prior to throwing parts at it.
Bottom line, you can borrow a cooling system pressure tester at some auto parts stores either free or a small fee. Follow the directions and trouble shoot prior to throwing parts at it.
Thread
Thread Starter
Forum
Replies
Last Post
