How much to spend on head gasket repair

rjaywhit · Post by **rjaywhit** » 23 Feb 2010, 07:34

I am trying to make a decision on how best to repair a 850na that I bought last November for $400 US with 115K miles on working OD.

I bought the car knowing that it had a blown head gasket but everything else looked good.

Within a week I had the head off the engine and found the reason for the blown head gasket. It had a broken thermostat. The metal bracket on the top of the thermo broke loose and there was nothing for the spring to push against.

I am looking at approx $350 for parts and found a machine shop that can rebuild the head for $370. So for an additional cost of $720 I can get it running again.

My problem is that every month since I bought the car I have had unexpected expenses come up. So my repair money dissapears each month.

I am thinking that maybe my approach should be to only replace the essential parts (ie head gasket set and bolts) and get the machine shop to only test and shave the head.

I imagine that I would have to disassemble the valves before I took the head to the shop. I have never done a valve job before, is this something for a novice?

My hesitation on spending the full $720 is that I have never driven this car on the road. My fear is that I get the engine running again and then find out that the transmission is toast.

I did move the car under power about 30 feet both in D and R so I know that there is some kind of transmission and the brakes and steering do work.

Any advise?

Thanks.

panda · Post by **panda** » 23 Feb 2010, 08:15

If you go to craigslist.com or org
go to the cities in whereever you are

at the very bottom there is a services section
choose auto

there a a few deals that are better than the current shops
you have to research a bit to get some history but i got a quote from a reputable shop for 450. for a head gasket
timesa are getting tough and prices are becoming competetive
good luck to you

Post by **JDS60R** » 23 Feb 2010, 09:29

Pull that head gasket and clean up the block - lets check for cracks first. Then refer to my previous post you posted in the other thread .
1. Check for cracks
2. Check head and block for warp
3. Check for leaking valves
4. repair as needed

Post by **JDS60R** » 23 Feb 2010, 09:39

Please consider cleaning up the cylinders before you get rust pitting. To do so, remove the residue in there. Coat the cylinder well with some oil and cover the block. ( I wipe down the cylinders with oil and stuff oily paper towels in each cylinder and then cover with a folded towel I keep in the shop. If the car sits outside like this you will h ave to check it twice a week to keep the rust at bay as the oil will slowly run down the cylinder walls.

rjaywhit · Post by **rjaywhit** » 23 Feb 2010, 11:07

JDS60R wrote:Please consider cleaning up the cylinders before you get rust pitting. To do so, remove the residue in there. Coat the cylinder well with some oil and cover the block. ( I wipe down the cylinders with oil and stuff oily paper towels in each cylinder and then cover with a folded towel I keep in the shop. If the car sits outside like this you will h ave to check it twice a week to keep the rust at bay as the oil will slowly run down the cylinder walls.

Yeah, these pics are from early Dec after I pulled the head. I cleaned up the bores and every two weeks I spray some WD40 in the bores add some oil and rotate the crank about 10 times.

The block is covered with a plastic bag and a piece of cardboard cut in the shape of the head. I use some of the old head bolts to keep everything in place and protected.

Post by **charlyW** » 23 Feb 2010, 11:29

Clean the Bores and drain the block of coolant before the rust ruins the bores. $720 isn't a bad price if they're rebuilding the engine for you.

1: Check for cracks
2: Check for flatness/warpage
3: Run a paraffin test to see how badly the valves are leaking
4: Clean the block
5: Rebuild
6: You're happy bunny

I would work on getting the engine up and running before continuing to spend on the car. Previous poster has said it all get the head checked for cracks and warpage [you can check for warpage if you have a metal rule [not plastic] putting the rule to right angles to the combustion chambers then with feeler guages make a note of the gaps and for flatness put the rule length ways down the entire length of the head do the same and make a note then check against the figures in any good service manual.

Only if the head has warped above 0.005 inch will you need it skimmed as there is a limit to how many times these heads can be skimmed. Really dont understand why everyone goes to replace the cylinder head gasket and waste money on getting a head skimmed totally unecessay was very necessary on steel heads or diesel heads but alloy being a lot softer and never is the blocked skimmed so it's a pointless venture unless both are skimmed.

rjaywhit · Post by **rjaywhit** » 23 Feb 2010, 11:57

charlyW wrote:Clean the Bores and drain the block of coolant before the rust ruins the bores. $720 isn't a bad price if they're rebuilding the engine for you.

1: Check for cracks
2: Check for flatness/warpage
3: Run a paraffin test to see how badly the valves are leaking
4: Clean the block
5: Rebuild
6: You're happy bunny

I would work on getting the engine up and running before continuing to spend on the car. Previous poster has said it all get the head checked for cracks and warpage [you can check for warpage if you have a metal rule [not plastic] putting the rule to right angles to the combustion chambers then with feeler guages make a note of the gaps and for flatness put the rule length ways down the entire length of the head do the same and make a note then check against the figures in any good service manual.

Only if the head has warped above 0.005 inch will you need it skimmed as there is a limit to how many times these heads can be skimmed. Really dont understand why everyone goes to replace the cylinder head gasket and waste money on getting a head skimmed totally unecessay was very necessary on steel heads or diesel heads but alloy being a lot softer and never is the blocked skimmed so it's a pointless venture unless both are skimmed.

$720 is $370 for machine shop and $350 for parts (gasket set, bolts, TB, Tensioner roller, TB idler roller, Water pump, head cover sealant, water hoses, thermostat, tune up items.) I would put it back together again.

I checked the head with a metal framing square (don't know how true it is) and the only gap I found was lengthwise between cyl 2 & 3 which is where the gasket blew. The gap was 0.20mm which is within spec according to the Haynes manual.

Post by **charlyW** » 23 Feb 2010, 12:47

If the head is within the specs then IMHO there is no point spending money on the head going to the machine shop unless you're uncertain on whether its cracked and the metal square is going to be very flat not as flat another way to do flat test is get something like gravy salt mix it to a paste paint a thin layer on the face of the head then lay the head on a pane of glass where the mix stays on the head you have a warp or if you can get it engineers blue is best it's like an ink, gravy salt is a cheaper way and just as effective. Valves you can do yourself will take an evening; ok you can't cut the seats yourself but with a good relapping recutting is unecessary. Look around to see if you can get the same stuff cheaper engine shops will always boot the price up on parts does FCP Groten do them or a similar volvo parts supplier?

You can clean the head with simple household paraffin the same as an engine shop uses

Run a paraffin test by turning the head upside down so the valve heads are face up fill the combustion chambers with paraffin and wait for it to leak out if it does leak then thats the valves needing relapping to form a good seal and grinding paste is readily available from any good motor factor.

Post by **JDS60R** » 23 Feb 2010, 13:23

If haynes says its within spec you are ok. Knowing that I am stuck on my old habits.

I only put on heads that are dead flat unless the budget absolutely prohibits it. I do this to give myself the best possible outcome. This is the perfectionist in me and not the engineer.

The spec exists for a reason. You can do this and have it succeed without issue. We had a old Datsun that was at the edge of the spec and was reassembled with only valve lapping. It ran for years without issue.

Next perform the valve leak test and let us know what you find.

The parts price is fine but if you only need a valve or two recut then $370 is high.

When you take the valves out please take a close up of the seats in all of the cylinders, one at a time, so we can discuss any obvious defects.

Do you have a cam lock tool ? - I am starting to manufacture them and wonder what the distance between your cams is. Is it roughly 138mm?

rjaywhit · Post by **rjaywhit** » 24 Feb 2010, 04:55

Paraffin? Like candle wax? Where do you get it? How do you use it?