Ok, I have a 7.4 in a 98 K2500 Sub, with 225,xxx miles. I am losing water somewhere. It isn't consistant at all. I checked the fluids last Friday, before I took off, and they were fine. I check it this afternoon, and it's about three quarts low on coolant..!! Local shop said it had a "minute" leak at the intake. I have been chasing this leak for....since I got home in Nov. It doesn't leak alot, til now. But, where does it go..??? I had a puddle under the Sub, but not THAT much...( It has rained) Any ideas what it could be??
Thanks, Bill
P.S. This truck has served me well. It doesn't burn oil, has plenty of power, just has the usual maintanance stuff a 225xxx truck would have....




Sounds like the intake gasket may be leaking into an intake port in the head and getting burned in the cylinder. Might check the spark plugs and see if one or more are a different color.
Gary
99 K 1500 Suburban
78 Silverado Big 10 w/factory 454
1977 Formula
1976 Trans Am
1980 Honda CB900 Custom



Technology is great, when it Works,
And one Big Pain in the Ass When it Doesn’t.
Detroit Iron Rules, All the Rest are Just Toys.
94 GMC Burban, 5.7L (350), 4X4, Auto
86 GMC Burban, 350, 2 WD, Auto
79 GMC pickup plow truck, 400, Full time 4X4, Auto
86 Pontiac Fiero SE, 2.8L, Auto, only mid engine American car
See a Pattern yet?
15 year GM assembly line worker.


Yes intake leaks are common. I use a cooling system leak tester that I bought at NAPA to t/s those little leaks. Right now I've got a leak on a heater hose at the back of the block. With all that's going on right now, I'm just topping the coolant off every couple of days. When warmer weather gets here, I dive under the hood and fix it permanently.
There is no way to happiness....happiness is the way.
High Desert SoCal
93 K1500 burb (personal) 350 AT 3" Lift 250K+
02 Honda Civic LX
Looking for a 1990's Miata for an engine swap
one other place that gets over looked real often is the raditor cap. the system get warm and the cap allows some heat to escape and as this happens it will take some water or coolent vapor with it. after some driving the level will go down. pull the cap and look at the gaskets if not dry or cracked or bad looking you can coat it with some grease or vassiline and see if this helps if so replace with a new cap and coat the seal so it will serve you for a long time......mike
Michael Collins
1993 4X4 Suburban
many other toys as well
If you dont SMELL coolant I would lean toward gaskets as suggested. My 01 sub had same issue WITH smell and quickly found Ye old weep hole on pump with dribble .
Good Luck
Thanks All,
I sent the Subby back to the shop that we have look at it. They found a couple of things that were leaking. The shop told me the intake gasket was leaking, but very minute. I told them if the intake has to come off, I'll change the timing chain/ cam, and do a port match on the intake. They weren't real enthused about hearing that. The radiator was replaced about four months ago, along with the cap. So, the cap was tested too, not real happy about doing that either.Just make me happy kids. The water pump was checked too.... I'm just waiting for the heater core to start leaking...!!!!!!
I noticed last night, I have a small "spot" under the passenger side wheel well area...figures...
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